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AP0836
AP083601.EXE available
additional file
Space Vector Modulation Overmodulation with 8-bit Microcontroller
This Application Note shows capture/compare units C504, C508, C868, C164CI used implement space vector modulation three-phase voltage control inverter applications. Space vector modulation widely considered superior other forms sinusoidal PWM. simple algorithm overmodulation also demonstrated.
Author: Copeland Microcontroller Applications
06.99, Rel.
Space Vector Modulation Overmodulation with 8-bit Microcontroller
Introduction.3 Sinusoidal Voltage Generation Capture/Compare Units Methods Generating Sinusoidal Voltages.7 Sinusoidally Weighted (SWPWM).7 Space Vector Modulation (SVM).9 Overmodulation Microcontroller Implementation Variable Scaling/Resolution Optimized Software Structure Implementation Options Results Conclusions Appendix SVM.a51.28 REGC504.inc REGC508.inc
AP0836 ApNote Revision History Actual Revision Rel.01 Previous Revision: None Page Page Subjects changed (since last release) actual Rel. prev. Rel.
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
Introduction
There many ways generate sinusoidal voltages currents with 3-phase inverter. advantages disadvantages most popular methods have been discussed great detail some time. popular method generating sinusoidal voltages Space Vector Modulation (SVM). popular because generates higher voltages with total harmonic distortion. Another advantage that works very well with vector control (sometimes called field orientation) schemes induction motors. This section describes overall systems which this Application Note might useful.
signals with dead-time
Microcontroller
Phase Inverter
IGBT MOSFET Isolation
C504 C508 C868
Phase Induction Motor
Current Speed Position
Figure Simple Motor Control System Figure shows block diagram low-end motor controller using Infineon 8-bit microcontroller. current speed feedback used perform simple control functions, such stall run-away detection, even slip frequency compensation. computational limitations 8-bit microcontroller make high performance induction motor control (such vector control) impractical. high-end motor control systems, there possibilities shown Figure
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
signals with dead-time
Microcontroller
Phase Inverter
IGBT MOSFET Isolation
C164CI
Vector Control current Speed Postion
Phase Induction Motor
C164CI peforms control calculations space vector Modualtion
Speed/Postion Current 16-bit Controller
8-bit Controller
signals with dead-time
C16x
Vector Control Algorithm
C504 C508 C868
current Speed/Position
IGBT MOSFET Isolation
Phase Inverter
Phase Induction Motor
Space vector voltage (us)
C16x performs control calculations, C504, C508, C868 performs space vector moduation
Figure High Performance Motor Control System Figure 2a), C164CI used calculations coordinate transformations required control speed torque motor. addition this, special CAPCOM6 module C164CI used implement space vector modulation. obvious advantage this system that only chip needed overall system cost lowered. some cases, desirable split system into parts. Part system does control calculations part system actually generates inverter signals. This type structure allows generator (the 8-bit microcontroller) tightly coupled power stage allows complex computation done physically further away from motor. This type structure shown Figure 2b).
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
This application note describes algorithm implemented C164CI, C504, C508, C868 microcontrollers. Example software used demonstrate concepts using C504 C508. Sinusoidal Voltage Generation Capture/Compare Units
capture/compare units C164CI, C504, C508, C868 (CAPCOM6) designed control many types motors. controlling 3-phase motors, capture/compare unit used generate signals needed drive 3phase inverter, including necessary dead-time needed eliminate shoot-through current each phase. used create sinusoidal voltage creating fixed frequency signal adjusting duty cycle. duty cycle varies sinusoidally, will output voltage. always assumed that inductance motor will filter into smooth signal shown Figure
microcontroller output
Motor Voltage after motor filters
Figure Using create sinusoidal voltages
Capture/Compare units designed create variable duty cycle signals. Actually only "compare" feature Capture/Compare unit that used generation. Capture/Compare unit contains timer several compare registers. When timer value same compare register value, output either pulled high low. duty cycle output signal follows compare value linearly. CAPCOM6 unit compare registers timer that count from specified 16-bit "period" value. When timer reaches period value, reverses direction counts down This useful generating center aligned shown Figure
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
Period Value Compare Value (CCL0, CCH0) Campare Value (CCL1, CCH1) Timer Value Compare Value (CCL2, CCH2)
Figure CAPCOM6 module operating Mode (center PWM)
3-phase inverter control, CAPCOM6 modules capable producing compare outputs. each three pins shown Figure there additional (COUTx) which mimic pin. COUTx programmed follow exactly programmed follow complement pin. addition this, COUTx adjusted account dead-time needed prevent shoot-through current which destroy inverter. Figure shows single COUTx used control phase inverter.
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
Programmable dead-time
COUTx
Figure output with complementary COUTx output programmable dead-time
Methods Generating Sinusoidal Voltages
following sections describe different methods generating three phase sinusoidal voltages. Section briefly describes simple method generating sinusoidal voltages. This method been around quite some time subject other ApNotes. biggest disadvantage this method voltage generation that maximum amplitude fundamental frequency generated voltage only about inverter rail voltage. Section describes theory behind SVM. method sinusoidal voltage generation which generates voltages whose amplitude fundamental frequency approximately greater than less sophisticated methods. total harmonic distortion also less. Section describes overmodulation. Overmodulation increasing amplitude fundamental frequency even higher about 1.12 times rail voltage). Unfortunately overmodulation introduces more order harmonics increases total harmonic distortion.
Sinusoidally Weighted (SWPWM)
simple create three phase sinusoidal voltages create signal which very high constant frequency (compared frequency desired sinusoid) sinusoidally weighted duty cycle. This method sinusoidal will referred SWPWM. SWPWM implemented very simply placing sinusoidally weighted values into three compare registers CAPCOM6 module. CAPCOM6 module then used control transistors that make inverter. SWPWM advantage requiring very little calculation (assuming appropriate look-up tables used). Each three phases made generate sinusoid which degrees phase. sinusoidal phase voltages generate sinusoidal lineto-line voltages sinusoidal line-to-neutral voltages when connected balanced star
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
connected load shown Figure Since voltages sinusoidal, some algebraic tricks used scale generated voltages that lengthy multiply instructions avoided. should noted that phase voltage voltage motor terminal measured with respect inverter negative rail voltage. Line-to-line voltage voltage motor terminal measured with respect another terminal. Line-to-neutral voltage voltage motor terminal measured with respect neutral (center star connected load). major disadvantage this method sinusoid generation that magnitude fundamental frequency less than percent (~86.6%) inverter rail voltage. Figure shows plot frequencies generated when creating this type sinusoid. Notice that addition fundamental frequency, switching frequency (~20 kHz) harmonics also have significant magnitude.
agnitude (perc entage inverter rail voltage)
Figure Sinusoidal Compare Values produce sinusoidal phase, line-to-line, line-toneutral voltages with ideal filtering
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agnitude
(Hz)
Figure Spectrum line-to-line voltages Simple generation method
Space Vector Modulation (SVM)
more sophisticated method which provides higher voltage motor (with lower total harmonic distortion). Consider three phase inverter Figure Note that whenever transistor transistor off, visa versa. This makes easy adopt simple notation describing state inverter. example, state when transistors "on" (and course "off") represented with notation state where transistors denoted
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
Phase
Phase Phase
Figure Phase Voltage Source Inverter with Balanced star connected Load Using this notation, consider following sequence states: Running inverter through this switching sequence will produce line-to-neutral voltages shown Figure This mode operation called "six-step mode". Operating six-step mode allows full capabilities inverter. amplitude fundamental frequency six-step mode actually greater than inverter rail voltage. Unfortunately six-step mode also creates high magnitude order harmonics which cannot filtered motor's inductance. Space vector modulation uses six-step mode, smoothes steps through some sophisticated averaging techniques. example, voltage required that between step voltages, corresponding inverter states activated such that average step voltages produces desired output. develop equations needed generate this averaging effect, problem transformed into equivalent geometrical problem. first step this re-definition transform inverter voltages six-step mode into space vector. Space vectors similar phasors that they denoted magnitude angle. important note that space vectors phasors. Phasors used represent single time varying sinusoid. Space vectors used represent three spatially separated quantities which also vary time. three time varying quantities, which zero spatially separated degrees, then these quantities expressed single space vector.
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
Figure Line-to-Neutral Voltages "Six-step" mode Since three line-to-neutral voltages zero, they easily converted into space vector (us) using following transformation: Van(t) Vbn(t) ej2/3 Vcn(t) e-j2/3 Since components space vectors projected along constant angles -2/3, 2/3), easy graphically represent space vector shown Figure
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ej2/3
e-j2/3
Figure Transforming quantities into single space vector Usually, when creating space vectors, three time-varying quantities sinusoids same amplitude frequency that have degree phase shifts. When this case, space vector given time maintains magnitude. time increases, angle space vector increases, causing vector rotate with frequency equal frequency sinusoids. voltages Figure converted into space vector plotted complex plane, seen that space vector takes distinct angles time increases (instead rotating smoothly would voltages were pure sinusoids). Figure shows values that space vector assumes time increase. goal space vector modulation generate appropriate signals that vector (us) produced. Consider space vector voltage located sector defined approximate applying percentage time (ta) percentage time (tb) such that: ta*u1 tb*u2 This leads following formulas U[cos() where |us| (Modulation Index)
given space vector angle sector modulation index approximation constructed applying vectors percentage times respectively. vector another sector, rotated multiple radians until sector times calculated then applied appropriate inverter states.
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
Sector
Sector
Sector
Sector Sector
Sector
Figure Values assumed Six-Step mode line-to-neutral voltage space vector
Figure Approximation
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Figure shows vector sector bounded (sector approximated. Like many other types PWM, space vector modulation creates pulses constant frequency (carrier frequency) with variable duty cycle carrier frequency should high enough audible range, high create excessive switching losses. period carrier will called approximate Figure inverter state that corresponds should active ta*T0 seconds, inverter state that corresponds should active tb*T0 seconds. When modulation index sufficiently small less than will less than one. This means that ta*T0 tb*T0 less than left over time voltage should applied motor. "left over" time will referred more formal: There ways apply voltage motor. first simply connect three phases negative rail inverter. This will called inverter state corresponding switching pattern second apply voltage motor connect three phases positive rail inverter. This will called inverter state corresponding switching pattern approximate voltage during carrier period, pulses timing shown Figure should used. obtain better total harmonic distortion, slightly different method applying switching states used. time split half applied beginning then more symmetric distribution pulses generated. This method known symmetric center-aligned space vector modulation. Figure shows symmetric space vector modulation implemented over consecutive carrier periods.
There implementations which carrier.
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ta*T0 Ctb*T0 t0*T0
Figure Pulses Generated Approximate
Cta*T0 tb*T0
tb*T0 ta*T0
Figure Pulses Generated Symmetric Space Vector Modulation
AP0836 6.99
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pulses shown Figure very similar those shown Figure easily generated using CAPCOM6 module. shown Figure switching frequency 1/(2*T0). When modulation index exceeds value become negative (depending angle). Since physically possible apply zero vectors negative time, maximum modulation index space vector modulation approximately 0.866. Graphically, this means that space vector modulation work properly, magnitude reference space vector, must small enough ensure that vector totally contained inside hexagon shown Figure When symmetric space vector modulation implemented with modulation index 0.866, ideal phase voltage (after filtering motor) shown Figure generated. phase voltage Figure same shape compare values that should used. These unusual voltages create sinusoidal line-to-neutral voltages expected) sinusoidal line-to-line voltages also generated.
agnitude (perc entage inverter rail voltage)
Figure Ideal (after filtering) Voltages Generated Space Vector Modulation shown Figure create sinusoidal line-to-line voltages which have amplitudes equal inverter rail voltage, even though modulation index only 0.866. also been proven produce lower current harmonics torque ripple than SWPWM. Figure shows frequency spectrum simulation with modulation index approximately 0.866. Figure shows, magnitude
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
fundamental frequency higher magnitude switching frequency lower than Figure
agnitude
Figure Spectrum Space Vector Modulation when modulation index ~0.866
Overmodulation
been proven that produce higher amplitude voltages than SWPWM, even modulation index limited 0.866. There several techniques that used extend this modulation index range. These techniques referred overmodulation. Figure shows graphical representation problem. Figure sector from hexagon Figure shown. Overmodulation needed when modulation index (the length reference space vector, causes head vector located outside hexagon. Figure will only become negative simple method overmodulation based angle, reference vector shown Table
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Figure Graphic Depiction modulation index 0.866
Angle
Modulation Index
Angle
Table When 0.866, performed with either When less than space vector modulation performed usual using Since head inside hexagon, will greater than zero everything will work properly. When between will less than zero. avoid this, performed using This will yield zero. When between again, will less than zero. avoid this, performed with Once greater than performed normally again with This method overmodulation will obviously produce line-to-line line-to-neutral voltages which `clean' normal space vector modulation, will allow modulation index exceed 0.866 will provide higher voltage motor. course, total harmonic distortion will increase. When modulation index reaches 1.000, overmodulation will produce signals equivalent six-step mode. six-step mode magnitude fundamental frequency ~112% inverter rail voltage.
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
values determined examining Figure where
Figure shows magnitude fundamental frequencies produced using SVM, overmodulation SWPWM.
(+),, Overmodulation l(o), W(*) SWPWM
angitude
Figure Fundamental Frequency Voltages SVM, Overmodulation SWPWM
Microcontroller Implementation
Microcontroller implementation overmodulation very difficult. equations complicated, overmodulation adds complexity. Proper scaling variables make computations much easier. Section describes variable scaling resolution used overmodulation implementation using C504 C508 8-bit microcontrollers. optimized flow chart overmodulation also given. section 4.2, issues regarding different versions CAMPCOM6 module discussed. There several implementation options which effect performance load. Section also discusses possible trade-offs designer should consider.
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Section shows results overmodulation implementation with C504 C508. Conclusions also given. Variable Scaling/Resolution Optimized Software Structure
implement SVM, microcontroller must receive perhaps even generate) reference space vector. usually convenient space vector given terms magnitude angle Given switching times calculated formulas: U[cos() first step should decide switching frequency. many cases, considered ideal switching frequency. Since CAPCOM6 unit will operate up/down counter, this means that timer period value should correspond kHz. With C504 operating with external oscillator, switching frequency about 19.6 obtained using divide prescaler CAPCOM6 module using period value 0x00FF. This convenient value since represented 8-bit value. also convenient scaled 8-bit value. engineering units, always between zero one, resolution will 1/255 0.00392. Since equations only valid between would easier represented 11-bit value. most significant bits used indicate sector, least significant 8-bits contain angle within sector with resolution /765 radians 0.235 degrees. This allows formulas valid long only byte used. look-up table used sine cosine that calculated, would require less computation values (0xFF fixed point) stored look-up tables. values then looked-up scaled appropriate value creates table case when easily seen that table exactly same table reverse. This means that only table needed. Table shows digital representation variables needed overmodulation.
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
Variable (|us|) (us) Digital Representation 8-bit value (0x00 0xFF) 11-bit value (0x0000 0x05FF) 8-bit value (0x00 0xFF) 8-bit value (0x00 0xFF) 8-bit value (0x00 0xFF) 8-bit value (0x00 0xFF) 7-bit value (0x00 0x7F) 8-bit values (0x00 0xFF) Engineering Unit Resolution 1/255 (~0.00392) /765 radians (~0.235 degrees) timer resolution (100 timer resolution (100 timer resolution (100 timer resolution (100 /765 radians (~0.235 degrees) /765 radians (~0.235 degrees) Comments Input Variable Bits contain Bits contain sector (input variable) ~19.6 Carrier Frequency (fixed) Stored table Table contains (0xFF) Stored table table used reverse Calculated ~(U*ta+U*tb)/256 Stored table Calculated needed from
Table Representation Variable needed Overmodulation CAPCOM6 unit relieves much computational work required space vector modulation. From Figure relationship between compare values determined. Table shows compare values phases chosen based sector which reference vector located.
Sector
Phase Compare Value
Phase Compare Value
Phase Compare Value
Table Compare Values Symmetric Space Vector Modulation
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Begin
0.866 Look-up
+30°
30°- Overmodulation
Jump Address XXYYh SECTOR (SECTOR+1)+(SECTOR
Sector 0102h) Sector 0204h) Sector 0306h) Sector 0408h) Sector 050Ah) Sector 060Ch) Look-up U*ta Look-up U*tb CCL2 CCL0 CCL1 Look-up U*tb Look-up U*ta CCL2 CCL1 CCL0 Look-up U*ta Look-up U*tb CCL0 CCL1 CCL2 Look-up U*tb Look-up U*ta CCL0 CCL2 CCL1 Look-up U*ta Look-up U*tb CCL1 CCL2 CCL0 Look-up U*tb Look-up U*ta CCL1 CCL0 CCL2
Figure Microcontroller Implementation Overmodulation
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Fortunately, 0xFF, simply simply ~(ta tb). Figure shows flow chart (optimized execution time) microcontroller implementation overmodulation.
Implementation Options
There several versions CAPCOM6 module. Each version "shadow latch" which allows compare values updated once. When compare registers written microcontroller, values actually stored shadow latch. When compare timer reaches count 0x0000, contents three shadow latches transferred real compare registers. This shadow latch mechanism ensures that three compare values updated simultaneously also guarantees that there disturbed pulses. Newer versions CAPCOM6 module (like modules C508, C868, C164CI) also allow shadow latch transfers when compare timer reaches period value. This allows non-symmetric actually better suited SVM. C504 only allows shadow latch transfers occur when compare timer reaches zero. Generally performed twice every switching period shown Figure properly implement this, shadow latch transfers must occur when compare timer reaches zero when compare timer reaches period value. Unfortunately, this possible with C504. However this does reduce load C504 50%. With most carrier based methods, microcontroller compare value calculation synchronized with carrier signal (the compare timer). This ensures more consistent latency between time that input values (us) received until pulses actually present output pins. This synchronization usually accomplished performing calculations after compare timer interrupt. CAPCOM6 module generate interrupts when compare timer reaches zero when timer reaches period value. This equivalent having interrupt beginning every Using these interrupts trigger calculations will ensure more consistent input output latency. Since C504 only allows shadow latch transfers compare timer zero matches, using only compare timer period interrupt will provide best latency. overmodulation have been implemented C504 C508. Appendix shows assembly source code. Conditional assembly switches used select between C504 C508. conditional assembly switch also used enable disable overmodulation. When implementing motor control application, there many factors which will influence load. Table shows some major factors their impact load when using algorithms Appendix should noted that switching frequencies shown Table obtained without changing algorithm. only modification needed change CAPCOM6 timer prescaler. Table shows only load algorithm (the compare timer ISR) without control loop. also assumes that 8-bit microcontroller instruction cycle time (e.g. C504 with C508 with external crystal).
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Space Vector Modulation Overmodulation with 8-bit Microcontroller
addition overmodulation, source code Appendix implements simple open-loop controller. channels used control amplitude frequency generated voltages.
Using Shadow Latch Transfer Switching Period Using Shadow Latch Transfers Switching Period
only w/Overmodulation only w/Overmodulation
Switching Frequency 19.6
Table Load assuming nsec instruction cycle
Results Conclusions
source code Appendix executed using C504 microcontroller Phytec evaluation board which comes with C504 Starter Kit. board equipped with external oscillator. code also tested C508 starter with external oscillator. this case switching frequency ~15.6 kHz. view output, either COUTx pins microcontroller connected external circuit shown Figure Capacitors used filter outputs voltages will appear smooth when viewed oscilloscope. source code Appendix uses analog inputs control magnitude frequency generated voltage. This portion code will omitted modified most applications. C508 board contains potentiometers converter reference voltages connected PCB, fewer additional components required. Accompanying this ApNote source code files Excel spreadsheet which used calculate look-up table values different dead-times needed.
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kitCON Connector Magnitude AN0/P1.0 CC1/P1.4 COUT1/P1.5 Frequency AN1/P1.1 CC2/P1.6 COUT2/P1.7 VAREF VAGND
kitCON Connector
Oscilloscope
C504
CC0/P1.2 COUT0/P1.3
100k
Figure External Circuit viewing output with Oscilloscope (for C504) Figure shows phase, neutral, line-to-neutral voltages when less than 0.866 (overmodulation active). Figure shows phase voltages line-to-line voltages same case. Figure shows phase, neutral line-to-neutral voltages when greater than 0.866 less than (overmodulation active). Figure shows phase, neutral line-to-neutral voltages when (six-step mode). these figures show, both symmetric overmodulation with switching frequency possible with Infineon microcontrollers CAPCOM6 unit.
Figure Phase, Neutral, line-to-neutral voltages 0.866
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Figure Phase line-to-line voltages 0.866
Figure Overmodulation Phase, Neutral line-to-neutral voltages 0.866
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Figure Overmodulation Phase, Neutral line-to-neutral voltages when
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Appendix
SVM.a51
Space Vector Modulation Infineon C504 C508 Microcontrollerincluding Overmodulation. Switching frequency 19.6 when external oscillator used with C504. Switching frequency 15.6 when external oscillator used with C508. Modulation Index (Magnitude) controlled channel (P1.0) C504 channel (P4.0) C508. Frequency controlled channel (P1.1) C504 channel (P4.2) C508. ;;05/99 ;;Keil Version Conditional Assembly Variables ;$SET (C508 Select C508 "C504 C504 $SET (C504 $SET (OVERMOD OVERMOD allows overmodulation code assembled. OVERMOD does allow overmodulation code assembled. Overmodulation allows higher voltage generated requires additional instruction cycles. RESET Interrupt Vectors 000H RESET vector LJMP begin 043H LJMP converter vector ADC_ISR
(C504) $INCLUDE (REGC504.INC) 06BH $ENDIF (C508) $INCLUDE (REGC508.INC) 0ABH $ENDIF LJMP CT1_ISR
C504 register file Capture/Compare Timer vector
C508 register file Capture/Compare Timer vector interrupt vector
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Variables VARIABLES SEGMENT data rseg VARIABLES ;Capture/Compare variable (needed SVM) ta_b: temporary storage ;Main Loop Variables Main_alfa: Main_sector: Freq:
copy ALFA used Main Loop copy SECTOR used Main Loop Value added previous alfa (determines frequency)
BIT_VARIABLES rseg DBIT
SEGMENT BIT_VARIABLES
handshake that allows ALFA/SECTOR updated asynchronously. means that CT1_ISR ALFA SECTOR. means that main loop update ALFA SECTOR
Equates Modulation Index SECTOR Sector Hexagon (angle SECTOR*pi/3 ALFA/255) ALFA Angle within sector 00100000B Shadow latch transfer CT1_INT_MASK 080H period interrupt CT1_INT_CLR 07FH (lower latency)
Main Code MAIN SEGMENT code rseg MAIN
begin: ;;;;;;;;;;;;;;;;;Initialize Variables #127 Stack Pointer beginning IDATA
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SECTOR, ALFA, Freq, Main_alfa, Main_sector, converter Enable access P1ANA Enable P1.0 P1.1 Disable access P1ANA Divide prescaler, Channel
;;;;;;;;;;;;;;;;;;;Initialize (C504) SYSCON, #010H P1ANA, #00CH SYSCON, #0EFH ADCON1, #80H $ENDIF (C508) ADCON1, #40H $ENDIF IEN1, #01H ADDATL
Divide prescaler, Channel Enable Interrupt Start conversion
;;;;;;;;;;;;;;;;;;;Initialize Capture Compare Unit COINI, #02AH Initial value COUTx CMSEL0, #033H COUTx compare mode CMSEL1, #003H CCPH, Period value 0x00FF CCPL, #0FFH CT1OFL,#10 Offset usec with Fosc/4 40MHz C504) CCIE, #CT1_INT_MASK Enable interrupt (C504) IEN1, #020H Enable Capture compare interrupts $ENDIF (C508) IEN2, #020H Enable Capture compare interrupts $ENDIF IP1, #020H Capture Compare Interrupt High Priority, Priority SETB Enable global interrupts CT1CON, #089H Start count Fosc/4 (19.6 with period value 0x00FF MHz) main_loop: ;;;;;;;;;Simulate control loop updating ALFA SECTOR main_loop Make sure update ALFA/SECTOR Freq Update Alfa divide result have Main_alfa least alfa's each sector Main_alfa, ALFA, ADDC Main_sector increment SECTOR ALFA rolls over Main_sector, SECTOR, CJNE SECTOR, No_Rollover SECTOR then rollover
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Main_sector, SECTOR,#0 No_Rollover: SETB
ALFA updated allow updated
main_loop
Compare Timer Interrupt Service Routine (performs SVM) Overmodulation performed OVERMOD Overmodulation performed OVERMOD ISR_CT1 SEGMENT code rseg ISR_CT1 CT1_ISR: PUSH PUSH CCIR, #CT1_INT_CLR OK_to_update
Clear Interrupt Request Make sure ALFA/SECTOR have been updated main loop
RETI instruction cycles OK_to_update: (OVERMOD) Overmodulation: sqroot3/2 PI/6 alfa alfa1 Then alfa1 sqroot3/2 PI/6 alfa alfa2 Then alfa2 alfa1 PI/6 delta, alfa2 PI/6 delta delta stored look-up table function ;;;;;;;;;;;;;;;;;;;; SQRT(3)/2 #(255-221) negative when alfa OVERMOD_EXIT ;;;;;;;;;;;;;;;;;;;;;;;; LOOK_UP DELTA DPTR, #delta_TABLE MOVC DPTR ;;;;;;;;;;;;;;;;;;;;;;;; ALFA PI/6? ALFA ACC.7, TRY_ALFA2 ;;;;;;;;;;;;;;;;;;;;;;;; ALFA1 ALFA PI/6? #128 SUBB SUBB ALFA UPDATE_ALFA
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SJMP OVERMOD_EXIT TRY_ALFA2: ;;;;;;;;;;;;;;;;;;;;; PI/6 ALFA ALFA2? #080H SUBB OVERMOD_EXIT UPDATE_ALFA: ALFA, instruction cycles OVERMOD_EXIT: $ENDIF JUMP appropriate sector (Messy saves instruction cycles!) SECTOR DPL, DPH, DPTR instruction cycles CSEG 0102H SECTOR calculate U(cos(alfa) 1/sqroot3*sin(alfa)) looked from table since table same table reverse ALFA DPTR, #tb_TABLE ta/U function alfa ~Alfa MOVC @A+DPTR ta/U ta_b, store instruction cycles calculate 2*U*(1/sqroot3)*sin(alfa) tb/U stored look-up table ALFA MOVC @A+DPTR tb/U instruction cycles calculate t0/2, ~t0/2 t0/2 these compare values ta_b SETB ~t0/2
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CCL2, t0/2 CCL0, ta_b t0/2 CCL1, CT1CON, #STE RETI instruction cycles, total CSEG 0204H SECTOR calculate 2*U*(1/sqroot3)*sin(alfa) tb/U stored look-up table ALFA DPTR, #tb_TABLE tb/U function alfa MOVC @A+DPTR tb/U ta_b, store instruction cycles calculate U(cos(alfa) 1/sqroot3*sin(alfa)) looked from table since table same table reverse ALFA ~Alfa MOVC @A+DPTR ta/U instruction cycles calculate t0/2, ~t0/2 t0/2 these compare values ta_b SETB ~t0/2 CCL2, t0/2 CCL1, ta_b t0/2 CCL0, CT1CON, #STE RETI
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instruction cycles, total CSEG 0306H SECTOR calculate U(cos(alfa) 1/sqroot3*sin(alfa)) looked from table since table same table reverse ALFA DPTR, #tb_TABLE ta/U function alfa ~Alfa MOVC @A+DPTR ta/U ta_b, store instruction cycles calculate 2*U*(1/sqroot3)*sin(alfa) tb/U stored look-up table ALFA MOVC @A+DPTR tb/U instruction cycles calculate t0/2, ~t0/2 t0/2 these compare values ta_b SETB ~t0/2 CCL0, t0/2 CCL1, ta_b t0/2 CCL2,A CT1CON, #STE RETI instruction cycles, total CSEG 0408H SECTOR calculate 2*U*(1/sqroot3)*sin(alfa) tb/U stored look-up table ALFA
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DPTR, #tb_TABLE tb/U function alfa MOVC @A+DPTR tb/U ta_b, store instruction cycles calculate U(cos(alfa) 1/sqroot3*sin(alfa)) looked from table since table same table reverse ALFA ~Alfa MOVC @A+DPTR ta/U instruction cycles calculate t0/2, ~t0/2 t0/2 these compare values ta_b SETB ~t0/2 CCL0, t0/2 CCL2, ta_b t0/2 CCL1, CT1CON, #STE RETI instruction cycles, total
CSEG 050AH SECTOR calculate U(cos(alfa) 1/sqroot3*sin(alfa)) looked from table since table same table reverse ALFA DPTR, #tb_TABLE tb/U function alfa ~Alfa MOVC @A+DPTR ta/U ta_b, store instruction cycles
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calculate 2*U*(1/sqroot3)*sin(alfa) tb/U stored look-up table ALFA MOVC @A+DPTR tb/U instruction cycles calculate t0/2, ~t0/2 t0/2 these compare values ta_b SETB ~t0/2 CCL1, t0/2 CCL2, ta_b t0/2 CCL0, CT1CON, #STE RETI instruction cycles, total
CSEG 060CH SECTOR calculate 2*U*(1/sqroot3)*sin(alfa) tb/U stored look-up table ALFA DPTR, #tb_TABLE tb/U function alfa MOVC @A+DPTR tb/U ta_b, store instruction cycles calculate U(cos(alfa) 1/sqroot3*sin(alfa)) looked from table since table same table reverse ALFA ~Alfa MOVC @A+DPTR ta/U
AP0836 6.99
Space Vector Modulation Overmodulation with 8-bit Microcontroller
instruction cycles calculate t0/2, ~t0/2 t0/2 these compare values ta_b SETB ~t0/2 CCL1, t0/2 CCL0, ta_b t0/2 CCL2, CT1CON, #STE RETI instruction cycles, total
Converter (Gets values Freq) ISR_ADC SEGMENT code rseg ISR_ADC (C504) UCHANNEL Channel FCHANNEL Freq Channel $ENDIF (C508) UCHANNEL Channel FCHANNEL Freq Channel $ENDIF (can pots starter kit) ADC_ISR: PUSH PUSH
Clear Interrupt Request Determine Channel Freq Channel ready
IADC ADCON1 #07H Freq_Read
ADDATH ADCON1, #0F8H ADCON1, #FCHANNEL ADDATL ADC_ISR_EXIT Freq_Read: Freq, ADDATH ADCON1, #0F8H
Update Start conversion Freq Channel
Update Freq
AP0836 6.99
Space Vector Modulation Overmodulation with 8-bit Microcontroller
ADCON1, #UCHANNEL Start conversion ADDATL Channel ADC_ISR_EXIT: RETI
Look-up Tables Overmodulation TABLES SEGMENT code rseg TABLES
(OVERMOD) tb_TABLE: 000, 001, 016, 017, 031, 032, 046, 047, 062, 063, 077, 078, 091, 092, 106, 107, 120, 121, 134, 135, 147, 148, 160, 161, 172, 173, 184, 184, 195, 195, 205, 206, 215, 216, 224, 225, 232, 233, Values take into account 002, 003, 004, 006, 007, 018, 019, 020, 021, 022, 033, 034, 035, 036, 038, 049, 050, 051, 052, 053, 064, 065, 066, 067, 068, 079, 080, 081, 082, 083, 093, 094, 095, 097, 098, 108, 109, 110, 111, 112, 122, 123, 124, 125, 126, 136, 136, 137, 138, 139, 149, 150, 151, 151, 152, 161, 162, 163, 164, 165, 174, 174, 175, 176, 177, 185, 186, 187, 188, 188, 196, 197, 198, 198, 199, 207, 207, 208, 209, 209, 216, 217, 218, 218, 219, 225, 226, 226, 227, 228, 233, dead-time 008, 009, 023, 024, 039, 040, 054, 055, 069, 070, 084, 085, 099, 100, 113, 114, 127, 128, 140, 141, 153, 154, 166, 167, 178, 179, 189, 190, 200, 201, 210, 211, 219, 220, 228, 229, (see 010, 025, 041, 056, 071, 086, 101, 115, 129, 142, 155, 168, 179, 191, 201, 211, 221, 229, Tables.xls) 011, 012, 013, 027, 028, 029, 042, 043, 044, 057, 058, 059, 072, 073, 074, 087, 088, 089, 102, 103, 104, 116, 117, 118, 130, 131, 132, 143, 144, 145, 156, 157, 158, 168, 169, 170, 180, 181, 182, 192, 192, 193, 202, 203, 204, 212, 213, 214, 221, 222, 223, 230, 231, 231,
delta_TABLE: Used Overmodulation (see Tables.xls) 025, 034, 041, 047, 052, 057, 061, 065, 069, 073, 076, 079, 082, 088, 090, 093, 096, 098, 100, 103, 105, 107, 109, 111, 113, 115, 119, 121, 122, 124, 126, NOTE: last value changed alfa 0FFH used during overmodulation when 0FFH
$ELSE This tb_TABLE should used when overmodulation desired. re-scales modulation index that when 255, actual modulation index really 0.866. This table takes dead-time into account. tb_TABLE: 000, 001, 002, 003, 004, 005, 006, 007, 008, 009, 010, 011, 011,
AP0836 6.99
Space Vector Modulation Overmodulation with 8-bit Microcontroller
013, 027, 040, 053, 066, 079, 091, 103, 115, 127, 138, 148, 158, 168, 177, 185, 193, 200, 014, 028, 041, 054, 067, 080, 092, 104, 116, 127, 138, 149, 159, 168, 177, 186, 194, 201, 015, 029, 042, 055, 068, 081, 093, 105, 117, 128, 139, 150, 160, 169, 178, 186, 194, 201, 016, 030, 043, 056, 069, 081, 094, 106, 118, 129, 140, 150, 160, 170, 179, 187, 195, 017, 031, 044, 057, 070, 082, 095, 107, 118, 130, 141, 151, 161, 170, 179, 188, 195, 018, 031, 045, 058, 071, 083, 096, 108, 119, 131, 141, 152, 162, 171, 180, 188, 196, 019, 032, 046, 059, 071, 084, 096, 108, 120, 131, 142, 153, 162, 172, 180, 189, 196, 020, 033, 047, 060, 072, 085, 097, 109, 121, 132, 143, 153, 163, 172, 181, 189, 197, 021, 034, 047, 060, 073, 086, 098, 110, 122, 133, 144, 154, 164, 173, 182, 190, 197, 022, 035, 048, 061, 074, 087, 099, 111, 123, 134, 144, 155, 164, 174, 182, 190, 198, 023, 036, 049, 062, 075, 088, 100, 112, 123, 135, 145, 155, 165, 174, 183, 191, 198, 024, 037, 050, 063, 076, 089, 101, 113, 124, 135, 146, 156, 166, 175, 183, 191, 199, 025, 038, 051, 064, 077, 089, 102, 113, 125, 136, 147, 157, 166, 176, 184, 192, 199,
$ENDIF
REGC504.inc
WDTREL PCON TCON PCON1 TMOD P1ANA SCON SBUF ITCON IEN0 IEN1 P3ANA SYSCON WDCON
DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA
080H; 081H; 082H; 083H; 086H; 087H; 088H; 088H; 089H; 08AH; 08BH; 08CH; 08DH; 090H; 090H; 098H; 099H; 09AH; 0A0H; 0A8H; 0A9H; 0B0H; 0B0H; 0B1H; 0B8H; 0B9H; 0C0H;
Port Stack Pointer Data Pointer DPTR Byte Data Pointer DPTR High Byte Watchdog Timer Reload Register Power Control Register Timer control register RMAP==1: Power Control Register Timer/Counter mode control register Timer byte Timer byte Timer high byte Timer high byte Port RMAP==1: Analog Input Selector Register Serial control register SCON Serial data buffer Interrupt Trigger Condition Register Port Interrupt Enable Register Interrupt Enable Register Port RMAP==1: Analog Input Selector Register System Control Register Interrupt Priority Register Interrupt Priority Register Interrupt Request Control Register
AP0836 6.99
Space Vector Modulation Overmodulation with 8-bit Microcontroller
CT2CON CCL0 CCH0 CCL1 CCH1 CCL2 CCH2 T2CON T2MOD RC2L RC2H TRCON CP2L CP2H CMP2L CMP2H CCIE BCON ADCON0 ADDATH ADDATL ADCON1 CCPL CCPH CT1CON COINI CMSEL0 CMSEL1 CCIR CT1OFL CT1OFH DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA 0C1H; 0C2H; 0C3H; 0C4H; 0C5H; 0C6H; 0C7H; 0C8H; 0C9H; 0CAH; 0CBH; 0CCH; 0CDH; 0CFH; 0D0H; 0D2H; 0D3H; 0D4H; 0D5H; 0D6H; 0D7H; 0D8H; 0D9H; 0DAH; 0DCH; 0DEH; 0DFH; 0E0H; 0E1H; 0E2H; 0E3H; 0E4H; 0E5H; 0E6H; 0E7H; 0F0H; Compare timer control register Comp./Capture Reg. byte Comp./Capture Reg. high byte Comp./Capture Reg. byte Comp./Capture Reg. high byte Comp./Capture Reg. byte Comp./Capture Reg. high byte Timer Control Timer Mode register Timer Reload Capture register Timer Reload Capture register high Timer byte Timer high byte Trap enable control register Processor status byte Compare timer period register Compare timer period register high Compare timer compare register Compare timer compare register high Capture/compare interrupt enable Block commutation control register Converter Control Register Converter Data Register High Byte Converter Data Register Byte Converter Control Register Compare timer period Compare timer period high Accu, bitaddressable E0-E7 Compare timer control Compare output initialization register Capture/compare mode select register Capture/compare mode select register Capture/compare interrupt request flag Compare timer1 offset register Compare timer1 offset register high B-Register, bitaddressable F0-F7
EAN0 EAN1 EAN2 EAN3
088H; 089H; 08AH; 08BH; 08CH; 08DH; 08EH; 08FH; 090H; 091H; 092H; 093H; 098H; 099H; 09AH; 09BH; 09CH;
Interrupt control External interrupt edge flag Interrupt control External interrupt edge flag Timer control Timer overflow flag Timer control Timer overflow flag
Receive interrupt flag Transmit interrupt flag Received mode Send mode Enable serial reception
AP0836 6.99
Space Vector Modulation Overmodulation with 8-bit Microcontroller
INT0 EAN4 INT1 EAN5 EAN6 EAN7 SWDT WDTS OWDS CPRL2 EXEN2 TCLK RCLK EXF2 IADC 09DH; 09EH; 09FH; 0A8H; 0A9H; 0AAH; 0ABH; 0ACH; 0ADH; 0AFH; 0B0H; 0B1H; 0B2H; 0B2H; 0B3H; 0B3H; 0B4H; 0B4H; 0B5H; 0B5H; 0B6H; 0B7H; 0B8H; 0B9H; 0BAH; 0BBH; 0BCH; 0BDH; 0C0H; 0C1H; 0C2H; 0C3H; 0C8H; 0C9H; 0CAH; 0CBH; 0CCH; 0CDH; 0CEH; 0CFH; 0D0H; 0D2H; 0D3H; 0D4H; 0D5H; 0D6H; 0D7H; 0D8H; 0D9H; 0DAH; 0DBH; 0DCH; 0DDH; Serial Serial Serial Enable Enable Enable Enable Enable mode mode mode external interrupt timer overflow interrupt external interrupt timer overflow interrupt serial port interrupt
Serial port Input Serial port Output External interrupt input External interrupt input Timer/counter external count input Timer/counter external count input External data segment write signal External data segment read signal
Parity flag Overflow flag Register bank selector Register bank selector General purpose flag Auxiliary flag Carry flag
AP0836 6.99
Space Vector Modulation Overmodulation with 8-bit Microcontroller
WDTREL PCON TCON PCON1 TMOD XPAGE DPSEL SCON SBUF IEN2 IEN0 SRELL SYSCON IEN1 SRELH IEN3 IRCON CCEN T2CCL1 T2CCH1 T2CCL2 T2CCH2 T2CCL3 T2CCH3 T2CON CRCL CRCH CP2L CP2H CMP2L CMP2H CCIE BCON
REGC508.inc
DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA 080H; 081H; 082H; 083H; 086H; 087H; 088H; 088H; 089H; 08AH; 08BH; 08CH; 08DH; 090H; 091H; 092H; 098H; 099H; 09AH; 0A0H; 0A8H; 0A9H; 0AAH; 0B0H; 0B1H; 0B8H; 0B9H; 0BAH; 0BEH; 0C0H; 0C1H; 0C2H; 0C3H; 0C4H; 0C5H; 0C6H; 0C7H; 0C8H; 0CAH; 0CBH; 0CCH; 0CDH; 0D0H; 0D2H; 0D3H; 0D4H; 0D5H; 0D6H; 0D7H; Port Stack Pointer Data Pointer DPTR Byte Data Pointer DPTR High Byte Watchdog Timer Reload Register Power Control Register Timer control register RMAP==1: Power Control Register Timer/Counter mode control register Timer byte Timer byte Timer high byte Timer high byte Port Page Address Register XRAM Data Pointer Select register Serial control register SCON Serial data buffer Interrupt Enable Register Port Interrupt Enable Register Interrupt Priority Register Serial Channel Reload Register Byte Port System Control Register Interrupt Enable Register Interrupt Priority Register Serial Channel Reload Register High Byte Interrupt Enable Register Interrupt Request Control Register Capture/Compare Enable Register Comp./Capture Reg. byte Comp./Capture Reg. high byte Comp./Capture Reg. byte Comp./Capture Reg. high byte Comp./Capture Reg. byte Comp./Capture Reg. high byte Timer Control Timer Reload Capture rgister Timer Reload Capture register high Timer byte Timer high byte Processor status byte Compare timer period register Compare timer period register high Compare timer compare register Compare timer compare register high Capture/compare interrupt enable Block commutation control register
AP0836 6.99
Space Vector Modulation Overmodulation with 8-bit Microcontroller
ADCON0 ADDATH ADDATL ADCON1 CCPL CCPH CT1CON COINI CMSEL0 CMSEL1 CCIR CT1OFL CT1OFH CT2CON CCL0 CCH0 CCL1 CCH1 CCL2 CCH2 COTRAP EINT TRCON DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA 0D8H; 0D9H; 0DAH; 0DBH; 0DCH; 0DEH; 0DFH; 0E0H; 0E1H; 0E2H; 0E3H; 0E4H; 0E5H; 0E6H; 0E7H; 0F0H; 0F1H; 0F2H; 0F3H; 0F4H; 0F5H; 0F6H; 0F7H; 0F8H; 0F9H; 0FBH; 0FFH; Converter Converter Converter Port Converter Compare timer Compare timer Control Register Data Register High Byte Data Register Byte Control Register period period high
Accu, bitaddressable E0-E7 Compare timer control Compare output initialization register Capture/compare mode select register Capture/compare mode select register Capture/compare interrupt request flag Compare timer1 offset register Compare timer1 offset register high B-Register, bitaddressable F0-F7 Compare Timer Control Register Compare Timer Channel byte Compare Timer Channel high Byte Compare Timer Channel byte Compare Timer Channel high Byte Compare Timer Channel byte Compare Timer Channel high Byte Port Trap Register External Interrupt Enable Register Trap Control Register
INT4 INT5 EAN3 T2EX CLKOUT
088H; 089H; 08AH; 08BH; 08CH; 08DH; 08EH; 08FH; 091H; 092H; 093H; 095H; 096H; 097H; 098H; 099H; 09AH; 09BH; 09CH; 09DH; 09EH; 09FH;
Interrupt control External interrupt edge flag Interrupt control External interrupt edge flag Timer control Timer overflow flag Timer control Timer overflow flag
Receive interrupt flag Transmit interrupt flag Received mode Send mode Enable serial reception Serial mode Serial mode Serial mode
AP0836 6.99
Space Vector Modulation Overmodulation with 8-bit Microcontroller
INT0 INT1 EADC SWDT IADC IEX2 IEX3 IEX4 IEX5 IEX6 T2CM I2FR I3FR T2PS 0A8H; 0A9H; 0AAH; 0ABH; 0ACH; 0ADH; 0AEH; 0AFH; 0B0H; 0B1H; 0B2H; 0B3H; 0B4H; 0B5H; 0B6H; 0B7H; 0B8H; 0B9H; 0BAH; 0BBH; 0BCH; 0BDH; 0BEH; 0C0H; 0C1H; 0C2H; 0C3H; 0C4H; 0C5H; 0C6H; 0C8H; 0CAH; 0CCH; 0CDH; 0CEH; 0CFH; 0D0H; 0D1H; 0D2H; 0D3H; 0D4H; 0D5H; 0D6H; 0D7H; 0D8H; 0D9H; 0DAH; 0DBH; 0DCH; 0DEH; 0DFH; Parity flag Flag Overflow flag Register bank selector Register bank selector General purpose flag Auxiliary flag Carry flag Enable Enable Enable Enable Enable external interrupt timer overflow interrupt external interrupt timer overflow interrupt serial port interrupt
Serial port Input Serial port Output External interrupt input External interrupt input Timer/counter external count input Timer/counter external count input External data segment write signal External data segment read signal
AP0836 6.99
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