OMAP5910 SPRU689 SPRU671 SPRU672 SPRU673 SPRU674 SPRU675 SPRU676 SPRU677

PWL, PWT, and LED Reference Guide Literature Number: SPRU689 October 2003 IMPORTANT NOTICE Texas Instruments Incorporated and its

OMAP5910 OMAP5910 Dual-Core Processor PWL, PWT, and LED Reference Guide Literature Number: SPRU689 SPRU689 October 2003 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI's terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI's standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. 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Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation. Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not responsible or liable for any such statements. Following are URLs where you can obtain information on other Texas Instruments products and application solutions: Products Applications Amplifiers amplifier.ti.com Audio www.ti.com/audio Data Converters dataconverter.ti.com Automotive www.ti.com/automotive DSP dsp.ti.com Broadband www.ti.com/broadband Interface interface.ti.com Digital Control www.ti.com/digitalcontrol Logic logic.ti.com Military www.ti.com/military Power Mgmt power.ti.com Optical Networking www.ti.com/opticalnetwork Microcontrollers microcontroller.ti.com Security www.ti.com/security Telephony www.ti.com/telephony Video & Imaging www.ti.com/video Wireless www.ti.com/wireless Mailing Address: Texas Instruments Post Office Box 655303 Dallas, Texas 75265 Copyright 2003, Texas Instruments Incorporated Preface Read This First About This Manual The OMAP5910 OMAP5910 Pseudonoise pulse-width light modulator (PWL), pulse-width tone (PWT), and light-emitting diode (LED) modules are described in this document. Notational Conventions This document uses the following conventions. - Hexadecimal numbers are shown with the suffix h. For example, the following number is 40 hexadecimal (decimal 64): 40h. Related Documentation From Texas Instruments The following documents describe the OMAP5910 OMAP5910 device and related peripherals. Copies of these documents are available on the Internet at www.ti.com. Tip: Enter the literature number in the search box provided at www.ti.com. OMAP5910 OMAP5910 Dual-Core Processor MPU Subsystem Reference Guide (literature number SPRU671 SPRU671) OMAP5910 OMAP5910 Dual-Core Processor DSP Subsystem Reference Guide (literature number SPRU672 SPRU672) OMAP5910 OMAP5910 Dual-Core Processor Memory Interface Traffic Controller Reference Guide (literature number SPRU673 SPRU673) OMAP5910 OMAP5910 Dual-Core Processor System DMA Controller Reference Guide (literature number SPRU674 SPRU674) OMAP5910 OMAP5910 Dual-Core Processor LCD Controller Reference Guide (literature number SPRU675 SPRU675) OMAP5910 OMAP5910 Dual-Core Processor Universal Asynchronous Receiver/Transmitter (UART) Devices Reference Guide (literature number SPRU676 SPRU676) SPRU689 SPRU689 OMAP5910 OMAP5910 5 Trademarks Related Documentation From Texas Instruments / Trademarks OMAP5910 OMAP5910 Dual-Core Processor Universal Serial Bus (USB) and Frame Adjustment Counter (FAC) Reference Guide (literature number SPRU677 SPRU677) OMAP5910 OMAP5910 Dual-Core Processor Clock Generation and System Reset Management Reference Guide (literature number SPRU678 SPRU678) OMAP5910 OMAP5910 Dual-Core Processor General-Purpose Input/Output (GPIO) Reference Guide (literature number SPRU679 SPRU679) OMAP5910 OMAP5910 Dual-Core Processor MMC/SD Reference Guide (literature number SPRU680 SPRU680) OMAP5910 OMAP5910 Dual-Core Processor Inter-Integrated Circuit (I2C) Controller Reference Guide (literature number SPRU681 SPRU681) OMAP5910 OMAP5910 Dual-Core Processor Timer Reference Guide (literature number SPRU682 SPRU682) OMAP5910 OMAP5910 Dual-Core Processor Inter-Processor Reference Guide (literature number SPRU683 SPRU683) Communication OMAP5910 OMAP5910 Dual-Core Processor Camera Interface Reference Guide (literature number SPRU684 SPRU684) OMAP5905 OMAP5905 Dual-Core Processor Multichannel Serial Interface (MCSI) Reference Guide (literature number SPRU685 SPRU685) OMAP5910 OMAP5910 Dual-Core Processor Micro-Wire Interface Reference Guide (literature number SPRU686 SPRU686) OMAP5910 OMAP5910 Dual-Core Processor Real-Time Clock (RTC) Reference Guide (literature number SPRU687 SPRU687) OMAP5910 OMAP5910 Dual-Core Processor HDQ/1-Wire Interface Reference Guide (literature number SPRU688 SPRU688) OMAP5910 OMAP5910 Dual-Core Processor PWL, PWT, and LED Peripheral Reference Guide (literature number SPRU689 SPRU689) OMAP5910 OMAP5910 Dual-Core Processor Multichannel Buffered Serial Port (McBSP) Reference Guide (literature number SPRU708 SPRU708) Trademarks OMAP and the OMAP symbol are trademarks of Texas Instruments. 6 OMAP5910 OMAP5910 SPRU689 SPRU689 Contents Contents 1 Pseudonoise Pulse-Width Light Modulator Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.1 PWL Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.2 PWL Level and Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2 Pulse-Width Tone Module Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 PWT Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 PWT Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 PWT Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.1 Buzzer Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.2 Buzzer Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 14 15 17 17 18 3 LED Pulse Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 LED Pulse Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3 LED Pulse Generator Power Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 LED Pulse Generator Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 19 19 20 20 SPRU689 SPRU689 7 Figures Figures 1 2 3 4 8 OMAP5910 OMAP5910 Functional Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWL Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWT Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LED Pulse Generator Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 13 15 19 SPRU689 SPRU689 Tables Tables 1 2 3 4 5 6 7 8 9 10 11 12 13 14 PWL Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWL Level Register (PWL_LEVEL) Field Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWL Control Register (PWL_CTRL) Field Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWT Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWT Frequency Control Register (FRC) Field Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . PWT Volume Control Register (VRC) Field Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWT General Control Register (GCR) Field Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . Buzzer Frequencies (With 12 MHz PWT_CLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Buzzer Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LED Pulse Generator Control and Power Management Registers . . . . . . . . . . . . . . . . . . . . LPG Control Register (LCR) Field Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LED Blinking Period Control (PERCTRL) Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LED On Time (High Pulse Width) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Management Register (PMR) Field Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SPRU689 SPRU689 13 13 14 15 16 16 16 17 18 20 20 21 21 22 9 10 SPRU689 SPRU689 PWL, PWT, and LED The OMAP5910 OMAP5910 Pseudonoise pulse-width light modulator (PWL), pulse-width tone (PWT), and light-emitting diode (LED) modules are described in this chapter. Figure 1 shows the location of these modules on the OMAP5910 OMAP5910 Functional Overview. Figure 1. OMAP5910 OMAP5910 Functional Overview OMAP5910 OMAP5910 DSP private peripheral bus 16 32 DSP MMU TMS320C55x DSP (instruction cache, SARAM, DARAM, DMA, H/W accelerators) SDRAM memories 16 16 32 E M I F S E M I F F 16 SRAM 1.5 M bits JTAG emulation I/F McBSP3 MCSI1 MCSI2 Mailbox GPIO I/F 32 TIPB switch MPU bus Memory interface traffic controller (TC) MPU peripheral bridge 32 32 32 32 32 System DMA controller 32 MPU public peripheral bus UART1 UART2 UART3 IrDA MPU public peripherals McBSP2 USB host I/F USB function I/F I M I F 32 McBSP1 MPU/DSP shared peripherals MPU interface 32 DSP public peripherals DSP public (shared) peripheral bus 16 FLASH and SRAM memories DSP private peripherals Timers (3) Watchdog timer Level1/2 interrupt handlers 16 32 32 MPU core (TI925T TI925T) (instruction cache, data cache, MMU) ETM9 MPU private peripheral bus MPU private peripherals Timers (3) Watchdog timer Level 1/2 interrupt handlers Configuration registers Device identification Clock and reset management LCD I/F Osc Osc 12 MHz or 13 MHz 32 KHz I2C µWire Camera I/F MPUIO 32 KHz timer PWT PWL Keyboard I/F MMC/SD LED pulse gen(2) Frame adjustment counter HDQ/1-WIRE RTC 20 Clock Reset External clock request Figure 1 shows the PWL,PWT, and LED modules highlighted in the lower right corner as part of the MPU public peripherals. SPRU689 SPRU689 PWL, PWT, and LED 11 Pseudonoise Pulse-Width Light Modulator 1 Pseudonoise Pulse-Width Light Modulator Overview This pulse-width light (PWL) module provides control of LCD backlighting and keypad voltage by employing a 4096-bit random sequence generator. This voltage-level control technique decreases the spectral power at the modulator's harmonic frequencies. The module uses a 32-kHz clock from the ultra-low power device (ULPD) module on the Clock and Reset Management module. For more information on the ULPD module see SPRU678 SPRU678. 1.1 PWL Functional Description The PWL module is composed of a pseudorandom 8-bit data generator and a programmable threshold comparator (see Figure 2). The pseudorandom 8-bit data generator is built using a linear-feedback shift register (LFSR). It generates a white normal-law random value between 1 and 255. The LFSR polynomial generator output is P(x) = x[7] + x[3] + x[2] + x[1]. The comparator generates: - 0 if the random value is greater than or equal to the programmable threshold - 1 if the random value is less than the programmable threshold Assuming the random sequence is normal, it generates a sequence whose mean value is proportional to the comparator threshold. 12 PWL, PWT, and LED SPRU689 SPRU689 Pseudonoise Pulse-Width Light Modulator Figure 2. PWL Block Diagram RESET RESET 8-bit PRBS generator CLK32 CLK32 8 RESET A Comparator PWL_OUT A