AVR32 ISO26262 ATA6834 AEC-Q100 ATA6833 ATA6612/13 ATA6612 ATA66613 ATA6624 - Datasheet Archive
Atmel Automotive Compilation, Vol. 6 Standard Products Networking LIN AVR32: High-throughput 32-bit Microcontroller Architecture
4 Atmel Automotive Compilation, Vol. 6 Standard Products Networking LIN AVR32 AVR32: High-throughput 32-bit Microcontroller Architecture Addresses Tomorrow's Automotive Challenges Detlef Schick adaptive cruise control, lane depar- sis can be executed simultaneously ture warning or pre-crash systems without influencing the application improve the safety and help to negatively. The standardization of achieve 2001's target to cut the software via Autosar is driven by all amount of fatal accidents in the EU major OEM and will also increase in half by 2010. the software overhead significantly. Political aspects such as the European-wide reduction of the CO2 emissions are also reason for an Why Using an AVR32 AVR32 Microcontroller? increased demand of semiconductors in cars. No matter if it is called This brings us back to the initial The car industry has gone a long Efficient Dynamics, Blue Efficiency, question of why a high-throughput way since its beginning. Modern Blue Motion or whatever name the 32-bit microcontroller architecture cars contain 70plus Electronic Con- OEM have given their system they such as the AVR®32 is required trol Units (ECUs), and the amount of all use smart electronics to reduce to address tomorrow's automotive electronics in cars will continue to the gas consumption of their cars. challenges. Why can't designers just: increase significantly in the future. Start-Stop systems require battery By 2015 the amount of electronics monitoring and voltage stabilization is projected to be about 40% of the with DC-DC converters. Demand- value of a car. driven power steering and power brakes use BLDC motor controls, Electronics is the key enabler of 1. ncrease the clock speed of the I controller? 2. dd coprocessors or use dual/ A multiple cores? just to name a few of them. This could be done, of course, but today's innovations in the automotive industry. There is a virtually The increased complexity of these will it be the optimal solution? As unlimited amount of possibilities systems requires microcontrollers the power dissipation increases how electronics can be used in with high calculation performance. linear with the clock speed, the cur- future cars. The integration of mul- As complex systems are more vul- rent consumption in active mode timedia systems allow the driver to nerable to errors a great deal of will be twice as high if the clock stay focused. Active safety systems diagnosis functions is implemented speed is doubled. This might not and driver assistant systems such in software. Additional performance be a big issue if the engine of the as ESP, tire pressure monitoring, is required to ensure that the diagno- car is running but if the part lives on www.atmel.com a tight power budget, e.g., when is just usable for one specific pur- it wakes up from sleep mode to pose. Another disadvantage of check the status of a sensor, this coprocessor- or multi-core systems is a different story. As each process is the increased complexity of the technology has its speed limitations software development. an increase of the processor clock quite often requires to use a smaller The automotive market has three process geometry. This, however, fundamental requirements in per- means an increase of the leakage spective currents and thus a higher cur- Firstly, microcontrollers must have freely intermixable. It is designed rent consumption in sleep mode. a low current consumption to to minimize the code size and data Semiconductors of smaller process preserve the battery if the car is transactions between the core and geometries are more susceptible to parked but also to reduce the cur- memories, which saves both power "soft errors" in their memory which rent consumption and the related and CPU clock cycles. The com- are caused by Neutrons and Alpha CO2 consumption. Secondly, these piler automatically selects the most Radiation. As the internal signal controllers need to provide a high efficient compact or extended form levels are decreased with each pro- calculation performance under the of each instruction, providing the cess shrink the parts are also more described constraints. And third, user the fastest and most efficient susceptible the controller architecture has to code possible. The integrated DSP comply with future safety trends extensions such as, e.g., single- such as ISO26262 ISO26262. cycle multiply accumulate instruc- to electromagnetic fields. to future controllers. tions make this architecture particu- Adding a coprocessor or dual/multiple core is something which will The AVR32 AVR32 architecture with its larly suited for calculation-intensive be seen more and more in the auto- exceptionally throughput applications (such as digital filter- motive industry. For safety-critical was designed to address all three ing, FFT, decoding or decompres- systems this might be mandatory requirements. Atmel's UC3 family of sion of data). due to supervisor or redundancy Flash-based microcontrollers offers constraints. It also makes sense for up to 91 DMIPS at 66 MHz clock In many applications, such as net- high-performance systems to limit speed which outperforms all com- worked applications, it is important the current consumption and heat peting architectures in this class of to efficiently extract bit fields from dissipation. For specific applica- controllers. The innovative architec- a register, or insert bit fields into a tions, Atmel will also provide multi- ture was designed by Atmel engi- register for data packet handling. core solutions. neers, and 19 patents have been The AVR32 AVR32 ISA includes bit field filed. Some architectural highlights instructions such as bit field inser- are described in the following. tion and zero- or sign-extended But this is not a general solution high extraction. to overcome architectural weaknesses although it is, unfortunately, still common practice to boost the performance of 8-bit, Instruction Set Architecture (ISA) These instructions execute in one clock cycle only which is radically faster than most conventional architectures that rely on a sequence of shifts and logi- 16-bit and also weak 32-bit microcontrollers. Silicon costs are gener- The Instruction Set Architecture cal operations to perform the same ally higher if multiple cores have to (ISA) of the AVR32 AVR32 UC core has function. be implemented. And if the costs over are optimized, designers will end as 16-bit compact and 32-bit Microcontrollers wouldn't be what up in most cases with a part which extended instructions which are they are if it would not be for their 220 instructions available www.atmel.com 5 6 Atmel Automotive Compilation, Vol. 6 controlling abilities. This requires efficient bit manipulation of the internal configuration registers which typisequence: read the corresponding register change the relevant value using logical operators like OR and AND write the updated value Multiply Unit MUL cally consist of a multiple instruction Instruction Fetch Instruction Decode Prefetch Unit Register File Read Register File Write Decode Unit back to the register. The AVR32 AVR32 ALU Load / Store Unit LS instruction set includes atomic ALU Unit Read-Modify-Write instructions which perform all three instructions in one single cycle instruction: bit set, bit clear and bit toggle for any memory location. These are per- Figure 1. he 3-stage Single-cycle Pipeline with the Three Execution Sub T Units of the Third Stage formed by the memc, mems and real-time applications. It does not for instruction execution. The third contain a super scalar pipeline as stage is made of three execution The AVR32 AVR32 UC code is consis- with the AVR32 AVR32 AP7 architecture, sub-units: tently 5% to 20% smaller than code which comes with instruction and tion, and load/store units. The ALU compiled for the ARM® Thumb® data caches, data forwarding, haz- performs arithmetical and logical instruction set. More significantly, ard detection or branch prediction. operations, when code is optimized for execu- Instead the UC3 architecture has a division. The multiply unit executes tion speed, the AVR32 AVR32 UC code is pipeline which is optimized for a fast the numerous multiply and multiply- 30% to 50% more compact than execution speed with a determinis- and-accumulate (MAC) operations code compiled for the ARM instruc- tic timing behavior. The first pipeline available from the instruction set tion set. Executing a Fast Fourier stage pre-fetches one 32-bit or two architecture (ISA), and the load/ Transformation (FFT) shows a 40% 16-bit instructions every clock cycle store unit performs single-cycle performance gain of the UC3 com- into an internal instruction buffer. memory accesses to SRAM or pared to a comparable part based The buffer ensures that the pipe- accesses on the high-speed bus on ARM's new innovation, their line completely prevents pipeline (HSB). There are no data hazards CoretexM3 architecture. stalls during sequential program in the AVR32 AVR32 UC core so the regis- execution. Execution from on-chip ter files can be updated during the Flash can be sustained at the maxi- same clock cycle as the instruction mum CPU clock frequency without is executed. This makes assembly the CPU having to stall waiting for programming memt instructions. 3-stage Single-cycle Pipeline the ALU, including simpler multiplica- hardware compared instructions from the Flash. The to deeper pipelines as no code The 3-stage single-cycle pipeline of second stage decodes instructions scheduling is needed. the AVR32 AVR32 UC core is optimized for and generates necessary signals www.atmel.com Peripheral DMA Controller ture with dynamic frequency scal- helps to optimize the system's ing interconnects up to 16 High current consumption. Speed Bus (HSB) masters to up Data-intensive applications such to 16 HSB slaves. Current UC3 as networking applications, with products include up to 8 individual streams of data passing between bus layers. Different types of periph- the peripherals and the memo- erals require different bus frequen- ries, can seriously compromise the cies. For example, SPI and UART CPU. The on-chip multi-channel can get by with a substantially lower The AVR32 AVR32 UC core is the industry's peripheral DMA controller provides clock than a CAN, 10/100 Ether- first core with integrated single-cy- tight integration of peripherals and net MAC or high-speed USB. In a cle read/write SRAM as part of the memory, and is directly mapped conventional multi-layer bus struc- core itself. It has a direct interface to into the programming memory of ture, the fastest peripheral will dic- the CPU that bypasses the system each peripheral. Without DMA a tate the clock frequency of the entire bus to achieve faster execution, simple SPI communication will load bus. The UC3's peripherals are cycle determinism and lower power the CPU with 17.7% at 400 kBit connected through three individual consumption. Conventional micro- and with 53.4% at 1.2 MBit. The bus bridges (Bridge A to C) which controller architectures require one DMA of the UC3 architecture, how- can run at individual clock speeds. extra clock cycle as the SRAM is ever, offloads the CPU to a level Minimizing the speed of each of connected to the main bus which of only 0.4% load at 400 kBit and these three clock domains as well requires one clock cycle to output 1.2% at 1.2 MBit. Using the DMA in as the speed of the CPU and Matrix the address and a second one to Integrated Singlecycle Read/Write SRAM combination with the ADC allows to autonomously store ADC measurements in a predefined memory area for the CPU to analyze the acquired data in due time. This can be done while the CPU is in sleep mode Programmable Interrupt Controller OCD Power / Sleep Manager Single Step Control JTAG which can significantly reduce the power consumption as the core AVR32 AVR32 UC CPU Pipeline can stay in sleep mode during the acquisition phase. fetch which comprise a Harvard architecture, the Atmel engineers implemented an entire bus matrix. This ensures that the peripher- High Speed Bus Master CPU RAM High Speed Bus Master High Speed Bus Slave High Speed Bus two busses for instruction and data Data Memory Controller Instruction Memory Controller High Speed Bus Instead of only implementing the Trace Port Breakpoint / Watchpoint / Trace High Speed Bus Multi-layer Bus Architecture with Dynamic Frequency Scaling MPU AVR32 AVR32 UC Core als can operate independent from each other / the CPU, eliminating the wait states with are typically required in a system with a shared bus. The multi-layer bus architec- Figure 2. C3 Core Block Diagram with Tightly Coupled CPU SRAM Ensuring U Single-cycle Memory Access www.atmel.com 7 8 Atmel Automotive Compilation, Vol. 6 read/write the data. An HSB slave interface access allows DMA con- 99 DMIPS AVR32 AVR32 UC3 trollers or other HSB masters to 1 WS write to or read data directly from the closely coupled SRAM. Arbitra- 66 Competitor tion is performed if the CPU and a 2 WS high-speed slave request access simultaneously. The priority scheme is programmable to suit different 0 WS 33 1 WS application needs. 0 WS Interrupt Controller 0 0 10 20 30 40 50 60 70 MHz The UC3's interrupt controller has 64 groups of interrupts (each with Figure 3. ith Increasing Cpu Speeds the Fewer Wait State in the Flash W an individual autovector) and 4 Memory Access Accelerate the Performance Gain of the Uc3 different interrupt priority levels. In Compared to Completing Architectures. combination with the Non-Maskable Interrupt (NMI) this ensures is specified by the autovector. reading one instruction each CPU a fast and deterministic interrupt When resuming from the interrupt clock cycle, all 32-bit Flash micro- response and makes this part well handler, previously saved registers controllers introduce wait cycles in suited for the usage of operating are automatically popped from the their Flash access. Program caches systems. Pending events of a higher system stack before carrying out and the UC3's 16-bit instructions priority class may preempt handling the next instruction from the main help to reduce this effect to a mini- of on-going events of a lower pri- instruction flow. mum. In combination with the fast ority class. The CPU is also able to abort multi-cycle instructions if interrupt requests are pending dur- Flash function, this results in fewer Flash Performance wait cycles than with competitive solutions. ing more than 5 clock cycles, limiting the maximum interrupt latency The program is stored in the micro- to 16 cycles maximum. controller's on-chip Flash memory and it is directly executed from Memory Protection Unit When an interrupt is accepted, there. The Flash performance thus eight registers are automatically significantly influences the overall Operating systems for safety-critical stored to stack. The execution of performance of the controller. Since applications such as OSEK-compli- the interrupt handler routine then the Flash read-time is too slow at ant OS for the automotive indus- continues from the address which higher CPU speeds to support try require the usage of a control- www.atmel.com ler with a Memory Protection Unit sible in some cases but this intro- speed goes along with a reduction (MPU). The complexity of today's duces errors that require a thorough of the corresponding current con- applications is typically distributed analysis. With the UC3's on-chip sumption. on multiple tasks which run in par- FPU this can be avoided without allel. While task scheduling is done performance penalty. The UC3's current consumption is by the OS, the MPU controls the minimal, but even enables further access to the memory and prevents reduction since the two separate any unpermitted memory accesses. Conclusion peripheral bus bridges allow differ- If a protected memory location is ent clock frequencies to be set for authorization, The compact code as a result of high- and low-speed peripherals. an exception is executed. Atmel's the powerful and innovative instruc- This means slower peripherals can latest UC3 devices incorporate a tion set leaves less instructions to operate on a slower bus that draws Secure Access Unit (SAU) together execute less power. with the MPU. The MPU is set up to architectures. The directly coupled protect chunks of memory while the SRAM and the optimized 3-stage Atmel's UC3 portfolio is rapidly SAU provides a secure channel into pipeline both eliminate wait states expanding and currently consists specific memory locations that are and ensure a seamless and fast of six sub-families, each with a protected by the MPU. This gives code execution. The multi-layer bus peripheral set optimized for specific more flexibility and faster access to structure in combination with the market segments. The next edition protected areas. DMA functionality offloads the CPU or the Automotive Compilation will and allows parallel data processing. cover the powerful peripheral set Additional instruction cycles are and how an individual application saved as the efficient interrupt and can benefit from its innovative fea- exception handler allows fast task tures. accessed without Floating Point Unit Another architectural feature than with comparable switches and interrupt execution. driven by the automotive industry The combination of these inno- is the 32-bit Floating Point Unit vations have made the AVR32 AVR32 (FPU). An FPU provides numerous to what it is, and are the basis of advantages, one of which is the its exceptional high throughput. increased floating point operations Atmel's process technologies are accuracy. applica- one reason for its leadership in low- tion design and simulation is widely power microcontrollers. True low- used in today's designs. Tools power devices, however, also need such as Matlab and Simuink from l to MathWorks are used for complex since only a high throughput allows modeling and simulation; and they to reduce the number of power- use floating point values. A reduc- consuming memory accesses to a tion to fixed point numbers is pos- minimum. Lowering the CPU clock Model-based be high-throughput devices www.atmel.com 9 www.atmel.com As well as having 32k Bytes of High-temperature Capability 35 contains the microcontroller and the Flash memory, this controller has user interface. 2k Bytes of SRAM and 1k Byte of Both the ATA6834 ATA6834 and the ATmega- EEPROM memory. A special fea- 32M1 microcontroller are suitable The operating and diagnostic data ture is the integrated PWM genera- for use in high-temperature environ- are shown on a LCD display, which tor, which is known as the "Power ments. Both circuits are qualified in is also equipped with a touch panel Stage Controller" (PSC). The PSC accordance with AEC-Q100 AEC-Q100 grade 0. as user interface. The provided soft- can generate up to 6 PWM sig- This corresponds to an ambient ware has implemented a simple LIN nals with a resolution of 12 bits, temperature of up to 150 °C. protocol. The system can there- which are needed for the three half- fore be remotely controlled using a bridges of a BLDC motor control basic set of LIN commands. In both system. Up to 3 digital inputs or BLDC Application Board cases, the BLDC motor can be con- each output signal of the integrated veniently controlled, operating states The ATA6833 ATA6833 application kit shows PWM signal generation. This func- the entire BLDC motor control chain tion can be used for emergency from signal generation to signal shut-offs or for current-controlled amplification to the motor, and back motor control. The ATmega32M1 again with position signaling. The kit also has an internal 8-MHz RC consists of 2 units: The basic board oscillator with a PLL that generates with the power electronics, and the a frequency of up to 64 MHz, which controller board with the microcon- serves as an input frequency for the troller and the user interface. Commutation Steps 1 Hall Sensor Switches analog comparators can influence 2 3 4 5 6 1 H1 H2 H3 PSC. Thus, PWM frequencies of up t Commutation Steps The basic board is equipped with + motor. Only the commutation facil- A 1 H1 ity with Hall sensor feedback is sup- ported. The digital encoding is done by the microcontroller, which also timer, a 10-bit ADC with up to 11 H3 analyses the diagnostic signals and channels programmable controls motor operation accordingly. preamplifier, a 10-bit DAC and 4 The ATA6833 ATA6833's integrated charge analog comparators. The controller pump makes it possible to achieve + provides a LIN interface and a CAN A reverse polarity protection with little interface for communicating with voltage drop. This means that more the outside world. powerful motors can be used. B and a H2 t t - t C nected via a series of connectors, - t B + t C Commutation Steps + + The controller board, which is con- + t 1 2 3 4 5 6 1 S1+S4 such as an 8-bit timer and a 16-bit Switching Sequence for a motor controller are available, 3 Phases Output Voltage Other peripherals that are needed t S5+S4 6 S5+S2 5 S3+S2 4 S3+S6 3 S1+S6 2 S1+S4 Hall Sensor Switches 1 Com Figure 3. 6 Bridge Actuation B www.atmel.com 1 S1+S4 6 MOSFETs for operating a BLDC Switching Sequence 10-bit resolution. 3 Phases Output Voltage to 62.5k Hz can be generated with 2 Atmel Automotive Compilation, Vol. 6 such as speed, direction, duty cycle tation procedure is complexity dur- For simplicity's sake, block commu- and diagnostic states are displayed, ing implementation and the amount tation has been used in the ATA6833 ATA6833 and different methods to control the of microcontroller computing power application kit. MOSFETs can be selected. that is required, whereas block commutation is quick and easy to real- Actuation Procedure As well as the different commutation ize. methods, other methods of actuat- Unlike mechanically commutated DC Commutation Steps motors, the commutation of a BLDC tronically. This electronic commutation requires a specific switching sequence for all three half-bridges PWM Signals (Block Commutation) motor must be performed elec- 1 2 3 4 5 6 1 Current Flow (Block Commutation) 2 I A B C of the three coil phases (see figure 3). The switching sequence always depends on the rotor position, which is determined using Hall sensors, for example. Current Flow (Sine Commutation) I PWM Signals (Sine Commutation) 36 A B C The simplest type of commutation for BLDC motors is block commutation. With this procedure, the coil ampli- Figure 4. Sine Wave versus Block Commutation tude remains stable during one communication step. A somewhat more complicated method is sinusoidal commutation, whereby the amplitude is modulated in such a way that sinusoidal current flow is generated by the respective coil phase. Figure 4 S1 shows both methods. D1 S3 A D3 S5 B D5 C The advantage of sinusoidal commutation is the harmonic actuation sequence, which reduces vibration S2 D2 and the resulting amount of noise, which is much higher when using block commutation because of the "hard" switching sequence. The disadvantage of the sinusoidal commu- Figure 5. B6 Bridge S4 D4 S6 D6 www.atmel.com ing the B6 bridge are also available, The advantage of this method com- phase of the PWM signal of switch 1, i.e., two-quadrant and four-quadrant pared to the one described above a current is generated in the motor switching mode. is the quick change of rotating coil that flows through diode D2. In direction, whereas less switching order to now relieve diode D2, switch With the two-quadrant switching loss occurs with the two-quadrant S2 is switched through during the procedure, phase A is permanently switching method. The disadvan- blocking phase. Switch S2 is now switched to a potential, whereas tage of both methods is power loss actuated with the inverter PWM sig- phase B is switched to the oppo- and the resulting intrinsic heating nal of switch S1. site potential using a PWM signal. of the MOSFETs that occurs during An example can be seen in figure 5: the blocking phase of the PWM sig- This procedure can also be used If switch S4 permanently switches nal. The motor is idling at this time; during four quadrant chopper opera- phase B to ground, switch S1 clocks the continued rotation of the rotor tion by always actuating switches S2 phase A to the supply voltage. This induces current in the motor coil, and S3 with the inverted PWM signal is so-called high side clocking. How- which flows through the freewheeling of switches S1 and S4. This method ever, S1 can also be permanently diodes of the MOSFETs. is known as simultaneous, comple- switched through to the supply volt- mentary 4 quadrant switching. age, whereas S4 clocks to ground To reduce this power loss, the MOS- The motor actuation of the ATA6833 ATA6833 potential (low side clocking). The duty FET whose freewheeling diode is application kit can operate using cycle of the PWM signal determines loaded is switched through dur- either two-quadrant or four-quadrant the current flow through the coil and ing the blocking phase of the PWM switching operation, but the proce- consequently also the torque of the signal. An example (see figure 3) in dure for relieving the freewheeling motor. two quadrant chopper operation diodes is only supported in two- with high-side switching: Switch quadrant switching operation. When the synchronous four-quadrant S4 permanently switches phase B switching scheme is used, switches to ground, and switch S1 switches S1 and S4 are clocked simultaneously phase A to the supply voltage in a (high-side and low-side clocking). clocked manner. During the blocking More detailed motor control information can found on Atmel's website at: AVR motor control Application Note BLDC Driver www.atmel.com 37 38 Atmel Automotive Compilation, Vol. 6 Standard Products Networking LIN Switch Matrix Module Design Using LIN SiPs ATA6612/13 ATA6612/13 Markus Schmid Introduction ing years can be explained by the out so that the customers can use continued requirement for comfort the well-established AVR tools. It The LIN bus is well established functions in next-generation auto- also provides the same flexibility for in automotives where it is used for motives. As almost all comfort func- the applications as when using the low-cost and low-speed applica- tions can be controlled by the pas- discrete parts. tions as an alternative to the CAN sengers via keypads, it is expected bus. The implementation of the LIN that the amount of the keypads will bus is still increasing: in 2011 there also increase. This article covers are approximately 600 million LIN efficient keypad evaluation using a transceivers expected in all cars switch matrix module. The popularity of LIN devices can The easiest way to evaluate a push button is to connect it directly to an worldwide, and in 2014 this number is set to increase to 900 million. Handling Keypads LIN SiPs ATA6612 ATA6612 and ATA66613 ATA66613 I/O pin of a microcontroller. This is the preferred solution, when only a couple of push buttons need to be evaluated by a single microcon- in part be attributed to their flexibility: they can be used in many The ATA6612/13 ATA6612/13 consists of two troller. But with an increasing num- different Typical chips in a single package; the first ber of switches, the number of I/O LIN applications either evaluate one is the LIN system basis chip pins increases accordingly. In many the data of sensors or switches (LIN SBC) ATA6624 ATA6624, which has cases this leads to a need for larger or drive actuators like motors or a an integrated LIN transceiver, a and heating system. However, those LIN 5V voltage regulator, and a win- microcontrollers. Using a switch applications must not have high- dow watchdog. The second chip matrix the number of I/O pins speed or even real-time require- is an AVR 8-bit RISC automo- required can be reduced. Using a ments. Therefore, LIN devices can tive microcontroller. The ATA6612 ATA6612 3 x 2 matrix up to six push but- be found in window lifts, mirrors, or consists of the LIN SBC ATA6624 ATA6624 tons can be monitored using only keypads in car doors. They are also and the ATmega88 with 8-kBytes five I/O pins. With the conventional used in seat heating or adjustment, flash, while the ATA6613 ATA6613 includes solution where a single push but- in climate control, in the dashboard the ATA6624 ATA6624 and the ATmega168 ton is connected to one I/O pin, or for wiper control, where LIN is with 16-kBytes flash. The only dif- only five push buttons can be currently the unchallenged stan- ference between the two micro- evaluated. With more push but- dard. controllers is the size of the Flash tons, a switch matrix will lead to applications. ® therefore more expensive memory. All pins of the LIN System even greater savings in the number the Basis Chip as well as all pins of the of I/O pins required. For example, amount of LIN devices in the com- AVR microcontroller are bonded a 3 x 3 matrix can handle up to nine The expected increase in www.atmel.com PD7 VCC VS VCC S1 S2 S3 S4 S5 S6 100 nF S8 S9 S10 S11 S12 PB6 PB7 PD5 PD6 PB0 P7D PB1 PB4 PB5 PB2 1 GND2 VDD1 VDD2 S7 100 nF PB3 48 AVDD 100 nF S13 S14 S15 S16 S17 S18 PD3 GND4 ATA6612/13 ATA6612/13 PC0 WAKE MODE TM WD_OSC NRES PC5 PC6 TXD VCC INH PC4 RXD S24 PD2 S23 VS PD1 S22 EN PC3 S26 S27 S28 S29 S30 10 k VS PVCC KL_15 24 S25 WAKE 33 k NTRIG PD0 S21 LIN GND PC2 S20 220 pF LIN ADC7 PC1 S19 1k PD4 AREF 100 nF 36 GND1 ADC6 LIN Master pull-up + + 100 nF 10 µF S31 S32 S33 S34 S35 S36 51 k 10 k GND 100 nF 22 µF 10 k PD7 VBAT 100 nF 47 k KL15 Figure 1. Switch Matrix Application push buttons with six I/O pins lead- umns or rows. In general, pressing tially, reading the column result for ing to a saving of three I/O pins a key connects the key's row and each row, thus getting all pressed compared to the single push button column lines. When pressing the keys. per I/O pin solution. top left key, the left-most column line is connected to the top-most Switch Matrix Using LIN SiPs ATA6612/13 ATA6612/13 The illustrated pull-up resistors in row line. The microcontroller can the light blue area are very impor- detect this connection by scan- tant for the scan algorithm to moni- ning the columns and rows. When tor the push buttons. These do only single keys are pressed, a not necessarily have to be external Figure 1 illustrates an application quick method is to first select resistors; however, as internal resis- that can be commonly seen in cli- (drive low) all row lines and read tors are very high ohmic and many mate control panels. It shows a the column result. Then all column applications need to have a higher switch matrix serving some addi- lines are selected, and the row current through a closed push tional requirements. result is read. Returned column button; it is common to add more and row values are combined into low-ohmic, external resistors allow- The keyboard matrix is orga- a unique scan code for the specific ing a higher current to flow. Using nized in 6 x 6 push buttons (light key pressed. When the detection only the internal pull-up resistors green area), which enables the of simultaneous key presses is of the AVR will lead to a current of ATA6612/13 ATA6612/13 to handle up to 36 required, this method has to be approximately 160 µA through the push buttons. That is a very large slightly changed. The rows must pressed keys. number of push buttons, but it can be scanned separately. The row be easily reduced by removing col- lines must be driven low sequen- www.atmel.com 39 Atmel Automotive Compilation, Vol. 6 Almost all keypads in a contempo- of the keypads themselves. Shown the current consumption does not rary car have the ability to switch on in figure 1 as two variable resis- increase since the INH pin will be a backlight in order to illuminate the tors in the gray area, which can be switched off in this mode. push buttons. This enables the pas- evaluated using two of the available sengers to find the desired key even eight ADC channels. As the resis- The other external circuitry in the in a dark environment. The back- tors are connected to the supply dark green box in the schematic are light illumination consists of several voltage in this example, it is best to blocking capacitors for the micro- LEDs, whose brightness can be also use the supply voltage as ref- controller or, as the INH pin, relevant varied when they are controlled by erence voltage for the conversion. for the features of the LIN part. The a PWM pin of the microcontroller. It is also possible to choose a fixed resistor connected to the WD_OSC In the schematic, the four LEDs in internal 1.1V or an external refer- pin, for example, is important as it the yellow area are connected to ence voltage between 1.0V and the adjusts the watchdog frequency of the PWM pins PB1, PB2, PD5 and voltage connected to the AVCC pin the internal window watchdog. The PD6. In general, the ATA6612/13 ATA6612/13 of the microcontroller. In addition, circuitry connected to the WAKE, has up to six PWM pins. pin PD7 serves as an input for an KL_15, and the LIN pin is optional analog-to digital conversion. It is and can be adjusted to the needs In addition to the backlight illumina- connected via a voltage divider to of the application. tion in an automotive keypad, there the INH pin. Therefore, the module's are very often rotary encoders to battery voltage in standard opera- be evaluated by the microcontroller tion mode can be monitored very which also controls the evaluation efficiently. In current save mode S5 S6 S4 S5 S6 48 S10 S11 S12 100 nF 1 PB4 PB5 48 AVDD S10 S11 S12 100 nF GND4 PB4 PB5 AVDD AREF 100 nF 1 AREF 100 nF GND4 PC0 PC0 PC1 PC1 PC2 PC2 Figure 2. Current Flow During Simultaneous Key Presses PB3 S4 PB3 40 www.atmel.com Detection of Simultaneous Key Presses Current Consumption ing mode. The ATmega88/168 offers five different current saving modes Current consumption is, as in all with different active components electronic modules in cars, a key and wake-up sources. To continue Some additional hardware precau- parameter for the switch matrix. to scan the keys, the user should tions must be taken when detec- A current consumption limit of choose a power-saving mode with tion of simultaneous key presses is 100 µA in silent mode is the most a cyclic wake-up. After recognizing required. The schematic as shown common requirement, which is met a pressed key, the microcontroller in figure 1 may lead to erroneous by the ATA6612/13 ATA6612/13. The ATA6624 ATA6624 can then wake-up the ATA6624 ATA6624 as results, which is explained in the has two different current saving well as the complete LIN network, following. modes. The first is the sleep mode, and start the transmission of this which shuts down the watchdog, the event via the LIN bus after a master If the keys S5, S11 and S12 are LIN transceiver as well as the voltage request. With this set-up, no event pressed at the same time, the regulator. Thus, the microcontroller will be missed even in power-saving microcontroller will determine that remains currentless in sleep mode mode. key S6 is also pressed, although and it is not possible to continue to this is not the case. The current, scan the keys. The ATA6612/13 ATA6612/13's which flows when the three keys typical current consumption in sleep S5, S11 and S12 are pressed, mode is 10 µA. The second current The ATA6612/13 ATA6612/13 is a perfect choice is shown in figure 2 in red. The saving mode is the silent mode. In for applications where many keys microcontroller can not distinguish this mode the watchdog and the have to be monitored and the key whether the three pins are pressed LIN transceiver are switched off, press events have to be transmit- or if the key S6 is pressed. In order but the internal voltage regulator ted via the LIN bus. Figure 1 illus- to avoid this behavior an additional remains active, thus allowing the trates how such a module can be diode has to be included at every microcontroller to continue to scan built. However, in many cases it is key which stops the undesired cur- the keys. The ATA6624 ATA6624's typical necessary to adapt to the special rent flow and enables to achieve the current consumption in this mode is needs of a particular matrix. The correct result. Using these diodes 57 µA. The ATA6624 ATA6624 can wake-up ATmega88/168 included in the prevents undesired result. Shottky via a message on the LIN bus or ATA6612/13 ATA6612/13 is a standard micro- diodes are preferable as they have via an event at the pins WAKE or controller, therefore, the extensive a lower forward voltage compared KL_15. In order to achieve the application notes related to the to normal diodes. 100 µA limit, the microcontroller ATmega88/168 can also be used for must switch itself into a current sav- the ATA6612/13 ATA6612/13. Conclusion Application notes Atmega88/168 see id=3757 and id=3758 www.atmel.com 41 Atmel Automotive Compilation, Vol. 6 Standard Products Networking LIN LIN Node Mirror Positioning and Folding Rainer Boehringer incorpo- With the motor-foldable mirror, the In addition to the basic function rate a variety of functions. Previ- wing mirrors mirror can be brought into an oper- of mirror heating, side mirrors ously managed manually, bi-axial ating position or into a folded-in also boast many additional safety positioning was the first feature to position in which the mirror is less and convenience features includ- be automated. Recent advance- susceptible to accidents. Operat- ing electro-chromatic blank off, ments include a memory function ing circuitry enables a motor to be entrance lamps, direction indicator, where different mirror positions are activated by a switch, preferably antenna systems, distance warning, stored. With this memory function, by applying a voltage across the or sensor systems for modern traf- when reverse gear is engaged the motor with a polarity dependent on fic management systems. To con- mirror the desired direction of rotation of trol functions like heating or chro- the motor. matic blank off, ON/OFF switches automatically repositions from a driving position to a parking position. are sufficient. These functions can 16-bit SPI Open Load Detect Charge Pump Microcontroller Charge Pump Open Load Detect Battery Supply VCC Supply Charge Pump Open Load Detect Modern OUT1 OUT2 OUT3 Thermal Protection Figure 1. ATA6826 ATA6826 Block Diagram Open Load Power-on Reset Undervoltage Logout Open Load Control Logic Open Load 42 www.atmel.com be activated via external MOSFETs Part No. Minimum Short-circuit Current Thermal Resistance Junction Ambient troller. To control movement func- ATA6826 ATA6826 1A 65 K/W tions such as positioning and fold- ATA6827 ATA6827 1A 40 K/W ing, more intelligence is necessary T6818 T6818 1.5A 65 K/W directly controlled by a microcon- and smart drivers are required. Table 1. riple Half-bridge Output Driver Overview T without any additional protection cir- The ATA6826 ATA6826 is able to drive DC cuitry is possible. Open-load detec- motors up to 1A. Under normal cir- tion is also available to check the cumstances, this is sufficient for mir- electrical connection of the motors: ror positioning systems. For higher Mirror positioning is accomplished during activated state of the out- performances, the T6818 T6818, which using DC motors which require puts, the drivers feedback whether is capable of driving currents up advanced control. Integrated cir- a DC motor is connected or not. to 1.5A, can be used (see table 1). Drivers for Positioning Control cuits are typically designed as triple half bridges to be configured as two ATA6826 ATA6826 H-bridges. Two H-bridges are nec- VS = 6V to 40V essary to control two DC motors for ATA6816 ATA6816 the two-axes positioning of a rear µC SBC LIN mirror. The half bridges are each combined with two save-spacing on only during a HS switch on, bet- Connection to Door nous operation and that they switch SPI OUT2 OUT3 GND ATA6826 ATA6826 VCC OUT2 OUT3 GND (see figure 1). As these devices are fully protected against short circuits and overtemFigure 2. ATA6826 ATA6826 Application Schematic < 2A Fold on OUT1 ter EMC performance is achievable perature, connection of DC motors Left < 1A Right WD upper MOSFETs as NMOS, three integrated. Due to their asynchro- SPi OUT1 VCC out ADC LIN NMOS MOSFETs. To control the independent charge pumps are VCC VCC Up < 1A Down Optional: Position Feedback for Memory Function HALL or Resistive www.atmel.com 43 44 Atmel Automotive Compilation, Vol. 6 For motor-foldable mirrors, a cur- current. Security switch-off is pro- functions increases, so too does rent capability of about 3A is nec- tected by the clutches. the number of control lines, which essary. To meet this requirement, results in an increasingly complex two half-bridge outputs can be More advanced side mirrors can harness. To reduce this complexity, combined to achieve double out- be equipped with a memory func- a certificated bus system is indis- put current (see figure 2). A feature tion. With this function, the system pensable. The use of a single- of the NMOS output stages is the requires feedback on the posi- wire LIN bus reduces the wiring to positive thermal sensitivity shift. At tion. An additional potentiometer a minimum. Integrating voltage higher temperatures, the outputs' or angle sensor is required. By mea- regulator, resistance increases. The current of suring and storing the various mir- microcontrollers, Atmel's LIN SIPs the two combined outputs is auto- ror positions, these can be simply include all the required units to matically balanced. adjusted again. Due to the increas- complete the basic functions of an ing number of DC motors for seat, ECU to control a side mirror (see Mirror folding causes higher power steering and mirror adjustment, the figure 2). dissipation due to the higher cur- memory function is getting more rent. When using two triple half- and more important. LIN transceiver, and Figure 4 shows the integration of bridge drivers in the configuration mirror node and LIN cluster in the as shown in figure 2, the power dis- door electronics. In addition to the sipation is shared between the two Door LIN Node mirror control node, the block dia- devices. The benefit of this set-up is the distribution of the power dis- gram shows a node for window lift As the number of features and and a node for the switch unit. sipation between two sources. Stall condition and end stop are a challenge for the mechanical posi- LIN Bus tioning system. Usually, the block- LIN SiP ATA6616 ATA6616 ing currents of the DC motors are in the same range as the operating currents of the motors. The output driver cannot distinguish between operating and blocking condition. Actuators and Sensors for Various Functions 8-bit AVR® ATtiny87 As a motor-safety function, side mirrors are equipped with slipping clutches. And as such, there is no need to measuring the DC motor Figure 3. Block Diagram LIN SBC ATA6616 ATA6616 ATA6624 ATA6624 LIN SBC LIN Transceiver Voltage Regulator Watchdog www.atmel.com The control unit can be carried by a single device, a LIN SiP (see figure M 3). The control of a switch matrix enables the scanning of all the dif- Window Lift ferent user buttons. LIN Bus - Door Cluster The window lift module can completed using two devices: Atmel's ATA6823 ATA6823 H-bridge pre-driver with LIN transceiver, voltage regulator and watchdog to manage the supply and interface part; and Atmel's Control Unit Mirror Control Switch Unit Mirror ATtinyxx microcontroller with its integrated LIN UART for LIN protocol handling and movement control including the anti-pitch algorithm. All these functions need to fit into the casing of a side mirror. And on Appendix For further information see Package depending Figure 4. System Diagram Door LIN Cluster vehicle variants, even more functions will be added. Atmel's mirror solution enables man- Atmel Driver ICs http://www.atmel.com/products/drivers/default.asp Atmel LIN Networking http://www.atmel.com/products/lin/default.asp Atmel's Automotive Microcontrollers Application Note LIN Node Mirror Positioning and Folding ufacturers to use one basic system with a high rate of flexibility, allowing adding further features that can be produced via assembly variants. As all Atmel devices are available in very small QFN packages, these drivers and LIN SIPs can facilitate even the tightest designs. www.atmel.com 45 46 Atmel Automotive Compilation, Vol. 6 Standard Products Development Platform Evaluation Kit for Automotive Applications Juergen Strohal, Karl Militzer With automotive applications, the The new evaluation kit is a modular, ous application boards, an SD card increasing level of integration on the flexible application system to sup- slot, power supply connector, and a chip side demands a corresponding port customers in developing and beeper. While the daughter boards increased effort on the application evaluating their new applications. function as RF transmitter or trans- tool side. While customers, in gen- However, does flexible also mean ceiver, the application boards act eral, do not like dealing with differ- complicated and cumbersome to as an interface for the daughter ent stand-alone tools for each new use? Not with Atmel! The ATAPMxx boards to the system's two-wire application, there is an increasing was also designed to be easy-to- serial bus. The main board can need to evaluate complete sub-sys- handle. "Out of the box" operation manage and control a complete tems. Atmel's new automotive appli- was one of the main development application with different daughter cation development kit, ATAPMxx goals. with boards as a stand-alone system. addresses these needs. This is a the former car access application This is particularly useful if custom- tool that helps customers not only tool "RF design kit" do not need ers need to conduct a brief evalua- to develop their application but also to relearn completely new opera- tion of functions and performance, to evaluate application performance tion software as a nearly identical or if a ready-to-run demonstrator is in a single environment. It is flex- user interface is also supported by needed, which does not require a ible and modular, and allows easy ATAPMxx. The system offers the complex set-up procedure. extension for new devices. All for- hardware and software to develop mer tools from the car access area and demonstrate complete system For more elaborate evaluation, the have been integrated into this new solutions. Hardware and software main board can also be used as kit. Together with the upcoming documentation serves as a useful an interface to a PC. Using the AES devices Atmel is able to offer starting point for customers' devel- PC-based GUI, the system per- a system that can set up a com- opment. formance can be evaluated in all Customers familiar plete Remote Keyless Entry (RKE) details, new configurations can or a Passive Entry/Go (PEG) appli- The development kit comprises a be downloaded to certain compo- cation for both the car and the key main board as well as a selection of nents, and received or transmitted side. This kit is also currently being application and daughter boards, data can be displayed. The board expanded to include LIN network- depending on the designated appli- is powered by an AT90USB128 AT90USB128 ing capabilities so that the evalua- cation. The most important part is AVR® microcontroller which serves tion of complete LIN bus product the main board ATAPMMB with as USB connection to the PC, portfolio standard transceivers system controller, LCD display and and handles the touch panel and and system basis chips as well as touch screen, USB interface for PC the communication with the appli- LIN system-in-package solutions connection, two-wire-serial inter- cation boards that are connected is supported. face (TWI) as connector for vari- via the TWl. www.atmel.com Daughter Board ATAPM Main Board Daughter Board RF Application Board LF Application Board As shown in figure 1, a number immobilizer, system wake-up or To create a complete application, the of different application boards are inside/ outside detection of the key appropriate parts and correspond- available. These boards carry the are often realized by LF links. The ing boards must be selected. For daughter boards for the required LF application board that supports example, to design a bi-directional application and are equipped with these functions is quite similar to the PEG system with RF/RF-authen- TWI connectors on both ends so RF application board, it contains its tication channels, a mobile board that practically an unlimited num- own microcontroller (ATmega168), with the new, upcoming AES IC plus ber of application boards can be which is responsible for the appli- ATA58xx transceiver used as "key" attached in a row to a single main cation and the communication with are required. In addition, the main board. The standard RF application the main board via two-wire-serial board, an RF application board, board contains its own AVR micro- interface. Currently, the LF applica- and two LF application boards plus controller (ATmega168) to handle tion board supports two different two LF daughter boards are also the RF application as well as the functionalities, depending on the needed. The main board and appli- communication to the main control- attached daughter board; it can cation boards equipped with the ler on ATAPMMB. Various daughter operate as immobilizer base station appropriate daughter boards and boards can be connected via two (powered by U2270B U2270B), or it can be plugged together via TWI repre- rows of connectors on top of the used in a PEG application with a sent the "car" side of the system. application board. A wide variety of 6-fold antenna driver (ATA5279 ATA5279). Other configurations with mixed daughter boards with RF receivers or transceivers are already available from the well-known RF design kit, and the number of boards continuesly grows. An additional connector can also be used to attach a transmitter or transceiver board for configuration purposes. This can be Key disconnected from the RF application board once it is configured and can operate as a battery-powered mobile device. Some functions in remote keyless entry or passive entry (go) applications such as authentication/ Stand-alone PEG System Authentication RF RF LF Application Board with AVR Daughter Board Antenna Driver (ATA5279 ATA5279) LF Application Board with AVR Daughter Board Transponder Base Station (U2270B U2270B) LF Application Board with AVR AES IC + 3D-LF Coils + Transponder Coil + RF Transceiver (ATA5811/12/23/24 ATA5811/12/23/24) Daughter Board RF Transceiver (ATA5811/12/23/24 ATA5811/12/23/24) Car Main Board of Evaluation Kit ATAPMxx with AVR, Display, Keys and Interface PC-controlled PEG System PC-based GUI Figure 2. System Hardware Configurations for PEG www.atmel.com 47 48 Atmel Automotive Compilation, Vol. 6 RF/LF authentication channels are are requested more frequently, for point for newcomers, yet still offer also possible. example, remote keyless entry or full flexibility in that they can be passive entry go systems. These extended or adapted to other appli- While the new application platform fixed configurations facilitate to cation needs at any time by simply incorporates a fully modular con- address certain applications without ordering additional components. cept so that can be freely config- the need to study selection guides ured according to individual needs, or to get familiar with the details of The ATAPMxx has exhibited at Atmel also offers a number of fixed the ATAPMxx development plat- the Automotive Electronic Show configurations for applications that form. They are an ideal starting in Shanghai in April 2009 where it Content of Pre-configured ATAPM System Kits for Remote Keyless Entry RF 1-way Part Number of Single Boards \ Complete Kits Comment RF 2-way RKE1 ATAPMRF11-DK1 ATAPMRF11-DK1 ATAPMRF12-DK1 ATAPMRF12-DK1 ATAPMRF13-DK1 ATAPMRF13-DK1 ATAPMRF21-DK1 ATAPMRF21-DK1 ATAPMRF22-DK1 ATAPMRF22-DK1 ATAPMRKE1-DK1 ATAPMRKE2-DK1 Automotive Evaluation Kit System Controller ATAPM main board LCD, touch screen, USB-AVR, interface to PC & application ATAPMMB-DK ATAPMMB-DK ATAPMMB-DK ATAPMMB-DK ATAPMMB-DK ATAPMMB-DK ATAPMMB-DK ATAPMRFS-DK1 RF application board Standard for RKE & PEG ATAPMRFS-DK1 ATAPMRFS-DK1 ATAPMRFS-DK1 ATAPMRFS-DK1 ATAPMRFS-DK1 ATAPMRFS-DK1 ATAPMRFS-DK1 ATAPMLFS-DK LF application board For immobilizer base station & 3D-LF base station ATAPMLFS-DK ATAPMLFS-DK ATA5746-EK ATA5746-EK ATA5745-EK ATA5745-EK ATA5795-EK1 ATA5795-EK1 ATA5795-EK1 ATA5795-EK1 ATAPMMB-DK Application Boards RF Daughter Board with ATA5745/46-EK ATA5745/46-EK ATA5745/46 ATA5745/46 RF-Rx ATAB5760-S ATAB5760-S ATA5760 ATA5760 RF-Rx with SAW filter ATAB5761-N ATAB5761-N ATA5760 ATA5760 RF-Rx ATA5723/24-DK ATA5723/24-DK ATA5723/24 ATA5723/24 RF-Rx ATAB5811/12-B ATAB5811/12-B ATA5811/12 ATA5811/12 RF-TRx ATAB5823/24-B ATAB5823/24-B ATA5823/24 ATA5823/24 ATAB5760-S ATAB5760-S RF-TRx ATA5723-DK ATA5723-DK ATA5724-DK ATA5724-DK ATA5724-DK ATA5724-DK ATAB5812-B ATAB5812-B ATAB5811-B ATAB5811-B ATAB5812-RS ATAB5812-RS ATAB5811-RS ATAB5811-RS LF Daughter Board with ATA2270-EK2 ATA2270-EK2 U2270B U2270B ATAB5279 ATAB5279 ATA5279 ATA5279 Immobilizer base station 6-fold LF antenna driver Mobile Parts with ATAB5753/54 ATAB5753/54 ATA5753/54 ATA5753/54 RF transmitter for RKE ATAB5756/57 ATAB5756/57 ATA5756/57 ATA5756/57 RF transmitter for TPMS ATAB5749 ATAB5749 ATA5749 ATA5749 RF transmitter for RKE ATAB5811/12-RS ATAB5811/12-RS ATA5811 ATA5811 RF transceiver for remote start ATA5771/73/74-DK1 ATA5771/73/74-DK1 ATA5771/73/74 ATA5771/73/74 Tx-MCM ATA5795-EK1 ATA5795-EK1 ATA5795 ATA5795 ATA5790-EK1 ATA5790-EK1 ATA5790-3/-4-EK2 ATA5790-3/-4-EK2 ATA5790 ATA5790 + TX ATA5749 ATA5749 ATA5790 ATA5790 + TRX ATA5823/4 ATA5823/4 ATAB5753 ATAB5753 ATAB5754 ATAB5754 ATA5771-DK1 ATA5771-DK1 for RKE incl. Transponder function for PEG using RF/LFauthentication link for PEG using RF/RFauthentication link Table 1. Complete Configuration for Remote Keyless Entry Applications www.atmel.com served as the heart of a demonstra- ICs as well as development boards All kits come along with a selection tor for a remote keyless entry and and kits for a variety of Atmel's load guide, descriptions of hardware and immobilizer system. This devel- drivers. Due to the advance of LIN software, software library functions, opment platform, however, is not SiPs and the need to cross-link and guidelines for system set-up. restricted to applications in the different electronic control units car access application field. While it is useful to bridge LIN and car its current applications target the access systems. Therefore, a dedi- car access market (remote keyless cated LIN application board will be entry, passive entry/go, immobilizer, available within short. This board, and remote start), the next steps together with the main board, will involve additional functions such as convert the kit into a LIN master LIN bus connectivity, high-voltage node with minimum effort as the systems and further configurations basic software routines are bundled of existing application boards and with the LIN board. In addition, the daughter boards. Currently, Atmel integration of the load driver family provides into this development platform will several stand-alone well-accepted development tools for LIN transceivers, system basis enable the evaluation of complete door modules. chips and system-in-package (SiP) Content of Pre-configured Complete ATAPM System Kits for Passive Entry Go Application PEG1 Part Number of Single Boards \ Complete Kits Comment PEG2 ATAPMPEG-DK1 ATAPMPEG-DK2 ATAPMPEG-DK3 ATAPMPEG-DK4 ATAPMMB-DK ATAPMMB-DK ATAPMMB-DK ATAPMMB-DK Automotive Evaluation Kit System Controller ATAPM main board LCD, touch screen, USB-AVR, interface to PC & application ATAPMRFS-DK1 RF application board Standard for RKE & PEG ATAPMRFS-DK1 ATAPMRFS-DK1 ATAPMRFS-DK1 ATAPMRFS-DK1 ATAPMLFS-DK LF application board For immobilizer base station & 3D LF base station 2xATAPMLFS-DK 2xATAPMLFS-DK 2xATAPMLFS-DK 2xATAPMLFS-DK ATA5746-EK ATA5746-EK ATA5745-EK ATA5745-EK ATAPMMB-DK Application Boards RF Daughter Board with ATA5745/46-EK ATA5745/46-EK ATA5745/46 ATA5745/46 RF-Rx ATAB5760-S ATAB5760-S ATA5760 ATA5760 RF-Rx with SAW filter ATAB5761-N ATAB5761-N ATA5760 ATA5760 RF-Rx ATA5723/24-DK ATA5723/24-DK ATA5723/24 ATA5723/24 RF-Rx ATAB5811/12-B ATAB5811/12-B ATA5811/12 ATA5811/12 RF-TRx ATAB5823/24-B ATAB5823/24-B ATA5823/24 ATA5823/24 RF-TRx ATAB5823-B ATAB5823-B ATAB5824-B ATAB5824-B ATA2270-EK2 ATA2270-EK2 ATA2270-EK2 ATA2270-EK2 ATA2270-EK2 ATA2270-EK2 ATA2270-EK2 ATA2270-EK2 ATAB5279 ATAB5279 ATAB5279 ATAB5279 ATAB5279 ATAB5279 ATAB5279 ATAB5279 ATA5790-EK1 ATA5790-EK1 ATA5790-EK1 ATA5790-EK1 LF Daughter Board with ATA2270-EK2 ATA2270-EK2 U2270B U2270B ATAB5279 ATAB5279 ATA5279 ATA5279 Immobilizer base station 6-fold LF antenna driver Mobile Parts with ATAB5753/54 ATAB5753/54 ATA5753/54 ATA5753/54 RF transmitter for RKE ATAB5756/57 ATAB5756/57 ATA5756/57 ATA5756/57 RF transmitter for TPMS ATAB5749 ATAB5749 ATA5749 ATA5749 RF transmitter for RKE ATAB5811/12-RS ATAB5811/12-RS ATA5811 ATA5811 RF transceiver for remote start ATA5771/73/74-DK1 ATA5771/73/74-DK1 ATA5771/73/74 ATA5771/73/74 ATA5795-EK1 ATA5795-EK1 ATA5790-EK1 ATA5790-EK1 ATA5790-3/-4-EK2 ATA5790-3/-4-EK2 ATA5795 ATA5795 ATA5790 ATA5790 + TX ATA5749 ATA5749 ATA5790 ATA5790 + TRX ATA5823/4 ATA5823/4 Tx-MCM for RKE incl. transponder function for PEG using RF/LFauthentication link for PEG using RF/RFauthentication link ATA5790-3-EK2 ATA5790-3-EK2 ATA5790-4-EK2 ATA5790-4-EK2 Table 2. Complete Configuration for Passive Entry Go Applications www.atmel.com 49 50 Atmel Automotive Compilation, Vol. 6 Car Infotainment Radio Car Antenna Amplifier Concepts Stephan Gerlach With the antenna driver IC ATR4251 ATR4251, It is no surprise that the collected cially in a car with its inherent long- Atmel provides a very successful field strength results in a very low lasting temperature, humidity and solution for AM and FM antenna antenna voltage, which is even vibration test cycles. amplifiers. The device is mainly worse if loaded with the high capac- used in the cars radio's reception itance of a long antenna cable. To However, only combined integrated path facing challenging antenna avoid this, it is recommended to technologies e.g., BiCMOS as types positions provide, for example in AM band, used in Atmel's integrated antenna within the car body. The ATR4251 ATR4251's not only an LNA with an adjustable amplifiers can fully play its advan- advantages comprise high reliability gain but also a buffer to drive long tages over both discrete and simple and high functional density result- 50- or 75-Ohm cables. integrated CMOS solutions. An AM and reception ing in small design, maximum AC/ DC parameter repeatability during production and long-time stability. The IC's high flexibility enables to meet the individual customer needs antenna has a very high impedance Advantages of IC over Discrete Solutions especially in terms of cost and and a fairly low capacitance, resulting in low antenna voltage. For such an antenna, an FET transistor with a low input capacitance is the preferred choice as first stage amplifier There are various advantages of to match the antenna. It also needs antenna solutions using integrated to be taken into account that the As car design requirements more circuits over discrete solutions, high impedance and the far better and technical amongst others, stable operating noise/ linearity behaviour (com- aspects, however, the technical point against temperature variation, pared to a bipolar transistor within requirements for car antenna design component tolerances and aging, the AM frequency band) allow to also change. Since the amount of as well as a smaller design form fully use the small signal from the antennas in a medium- or luxury- factor which allows adding features antenna, and to handle large-signal class car easily reaches a number that improve the technical perfor- reception conditions that might of 20 to 30, current antennas need mance but are too cost-expensive occur during driving. to be almost invisible, or have at when realized as a discrete solu- least a decent appearance. Con- tion. Even if the amount of passive The receiver probably needs a sequently, antennas especially and active components within the long coaxial cable that may cause those for radio and TV reception integrated circuit exceeds those of a substantial loss due to its high tend to be integrated into the cars' a discrete solution, the stability and inherent capacitance. The best way windows. This is critical due to the reliability of an IC-based solution to overcome such a challenge is limited window area, and also due is far beyond the discrete solution. to attach a driver or buffer ampli- to the fact that different antenna This is due to the fact that each fier right before the cable. A smart compete for the best window area additional soldering connection is a biasing technique plus a push-pull position. potential failure root cause espe- circuit, comprising complementary performance ratio. more dominate www.atmel.com bipolar NPN and PNP transistors, A combination of different transistor Most advanced CMOS technolo- perfectly matches the requirements types is useful for all other antenna gies restrict the voltage swing more and will maintain the high linearity amplifier features such as auto- than necessary due to their inher- performance of the entire amplifier matic gain control (AGC), voltage ent low breakthrough voltages. By chain. stabilization, plug detection, over- using bipolar transistors, however, voltage and ESD protection. a maximum output voltage swing of noise quality and easy input-output For maximum linearity performance output of the FM stage, resulting matching, a bipolar transistor is the and best large-signal behaviour it is in excellent OIP3 (145 dBuV) and best choice as GaAs or compara- advantageous to use the entire bat- OIP2 (170 dBuV) values. ble solutions are too expensive in tery voltage range, provided that a most cases. well-stabilized regulation is in place. up to 12 Vpp can be achieved at the To achieve best FM amplifier low- OverVoltage Detection Supply 8V to 16V DC VS Voltage Regulator ATR4252 ATR4252 Reference Voltage FM Amp Pin Diode Driver Detector FM AGC AM/FM Antenna AGC Threshold AGC Time Constant Antenna Detection Antenna Cable AM/FM Combiner AM AGC Detector Pin Diode Driver AM LNA AGC Time Constant AGC Threshold AM Buffer Figure 1. ATR4252 ATR4252 Block Diagram www.atmel.com 51 Atmel Automotive Compilation, Vol. 6 For the functional block "AGC" it were carried out. The achieved amplifier part. If a maximum band- is also advantageous to use mixed results for the common base con- width of 30 MHz (especially for DRM circuitry, e.g., bipolar transistors as figuration are shown in figure 2, reception) has to pass the low-pass current sources for the PIN diode which illustrates the noise figure filter of the combination point net- attenuators because bipolar tran- comparison of final simulation run work, the noise figure will be about sistors require less space than and measurement within the 80- to 1.9 dB. For the most common AM comparable MOS transistors for 170-MHz FM frequency band. bandwidth of 450 kHz to 1.7 MHz, the same function. however, 3.5 Antenna Amplifier ATR4252 ATR4252 The ATR4252 ATR4252 is a further enhancement: it integrates even more external components, functional blocks and features, and the technical characteristics of the already existing blocks have been improved. 0.1 dB. This results in a final 2.5 noise figure of about 1.6 dB, 2.0 which is still a 1.5 very good value. 1.0 0.5 If the designer 80 90 100 110 120 130 140 Frequency in MHz NF / dB (measured) Performance Improvements the increase is only 3.0 NF in dB 52 150 160 170 NF / dB (simulated) wants to focus mainly on maximum linearity (more than 145 dBuV for OIP3) Figure 2. FM Amplifier Noise Figure and less on the NF performance, The ATR4252 ATR4252 provides outstand- Thanks to proper current density, this can easily be accomplished ing noise level and linearity perfor- dedicated biasing techniques and by adapting one external resistor mance in both separate as well as further means, the achieved NF of placed at the emitter of the FM tran- combined AM and FM band ampli- 1.5 dB in FM is even better than sistor. fiers. The goal for the FM amplifier results with dedicated discrete RF was to reduce the noise figure (NF) transistors, and matches well with A further reduction in BOM cost while maintaining the best possible the pre-running simulations. leads to the common emitter circuit intermodulation performance. When combining the AM and FM that can also be realized using the parts, however, it is inevitable to ATR4252 ATR4252. The benefit of cost and To perform this task, extensive sim- raise the FM noise figure at the board space reduction is accompa- ulations of the circuit, bond wires, combining point, depending on nied with a slight reduction in noise package and external components the required bandwidth of the AM and intermodulation performance. www.atmel.com AM Amplifier Overvoltage Protection and above the GND level) it can detect Antenna Detection a voltage window in the range of One of the AM amplifier design 0V to 3V, and 6V to 16V. The failure goals was to provide a voltage gain The antenna detection functional- signalization to the car's diagnos- of about 9 dB in addition to the ity is used to detect errors that may tic system is performed by a pre- insertion gain of the transimped- occur due to the following three defined DC current reduction of the ance amplifier used in ATR4251 ATR4251, main failure root causes: complete antenna amplifier down while keeping the noise and intermodulation level on the same level to 20 mA. 1. antenna plug that has not A as with ATR4251 ATR4251. been fit properly during car Finally the overvoltage protection This has been achieved by using a production unit is able to reduce the overall monolithic combination of MOS and 2. broken cable or a damaged A current consumption of the com- bipolar technology. The DC bias- reception structure of a printed plete IC to an innocuous value of ing of the relevant RF transistors, glass antenna 12 mA in case the applied DC volt- for example, has been optimized 3. temporarily bad cable conA for best noise and intermodulation nection to antenna that is performance. Since the ATR4252 ATR4252 caused by vibrations/ move- offers maximum modularity, it is ments of the car age exceeds 16V. Summary possible to insert an external filter between LNA output and buffer The ATR4252 ATR4252 enables to set-up Thanks to the device's outstanding input. Moreover, the voltage supply diagnostic system, which can be technical features, the new inte- range has been extended to lower realized as an additional plug con- grated antenna amplifier ATR4252 ATR4252 values (8V) without noticeable per- tact in the antenna-cable-amplifier enables to meet the car industry's formance reduction. chain or placed into the DC path of highest performance and quality a window heating field in case the requirements. Its inbuilt flexibility antenna is part of this structure. allows creating one standard plat- In all other cases where this lower form for the different car markets value is not needed, the ATR4252 ATR4252 provides a well stabilized and fil- This is possible because the inte- and antenna types, thus resulting tered supply voltage of 10V due to grated diagnostic system can both in cost-efficient and durable prod- the integrated voltage stabilization drive a current as well as detect a ucts. circuit and one external PNP power current that flows into the circuit. transistor. This stabilization loop is To realize one of the two possible able to suppress ripple and noise placements in the heating struc- by more than 40 dB. ture (just below the 12V level or just www.atmel.com 53 © 2009 Atmel Corporation. All rights reserved. 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