REG_PWM_DT3 = 0xA800A8 //PWM Channel Dead Time Register (168=2us for outputs PWM元,PWMH3) REG_PWM_DT2 = 0xA800A8 //PWM Channel Dead Time Register (168=2us for outputs PWML2,PWMH2) REG_PWM_DT1 = 0xA800A8 //PWM Channel Dead Time Register (168=2us for outputs PWML1,PWMH1) REG_PWM_DT0 = 0xA800A8 //PWM Channel Dead Time Register (168=2us for outputs PWML0,PWMH0) REG_PWM_CMR3 = 0x10000 //Channel Mode Register: Dead Time Enable DTE=1 REG_PWM_CMR2 = 0x10000 //Channel Mode Register: Dead Time Enable DTE=1 REG_PWM_CMR1 = 0x10000 //Channel Mode Register: Dead Time Enable DTE=1 REG_PWM_CMR0 = 0x10000 //Channel Mode Register: Dead Time Enable DTE=1 REG_PWM_ENA = REG_PWM_SR | B1111 //PWM Enable Register | PWM Status Register (activate channels 0,1,2,3) REG_PMC_PCER1 = REG_PMC_PCER1 | 16 //Peripheral Clock Enable Register 1 (activate clock for PWM, id36, bit5 of PMC_PCSR1) REG_PIOC_ABSR = REG_PIOC_ABSR | 0x3FCu //B1111111100, Peripheral AB Select Register Care needs to be taken to never read past the array size and to cycle back when i+shift >359.Īnyone interested in using the PWM engine (PWMH/PWML), this is the code I used to initialize the PWM and clock but it would need to be customized/cleaned up to suit your own application: //Configure PWM channels 0,1,2,3 (PWML0,PWMH0,PWML1,PWMH1,PWML2,PWMH2,PWM元,PWMH3), (port C.2,C.3,C.4,C.5,C.6,C.7,C.8,C.9), (pins P34,P35,P36,P37,P38,P39,P40,P41) In this case, the index values would be i, i+120, i+240. For 3 PWM output pairs (A,B,C) shifted by 120 degrees, the index values would be i, i+12000, i+24000.Īnother application requirement might have 1 degree phase control using one array with 360 data points. The rate of incrementing the index determines the filtered sine output frequency. The sine data array only needs to be one quadrant (90 deg) in order to create the full cycle of required data points. I've experimented with the PWM engine and was able to get 0.01 degree phase control resolution for a specific 3-phase power application. Its possible to use just one sine data array, then the index you use for each signal will determine the phase shift. I also think the PWM engine with its complementary pairs is best suited and probably required for this type of application. You can even get high resolution phase control, especially when generating low frequencies. Phase shifting PWM outputs is entirely possible. I can modify code if requested, but I think it's self explanatory to how to change the code. It takes 2 timers with 4 interrupts to do the PWM otherwise. You can access either through a timer library, or directly through the NVIC and setting registers directlyĮdit: I forgot to add that this is only for a 50% Duty Cycle. If(Interrupt = Max) Toggle Pin C Set Timer0 = 0 If(Interrupt = Max) Toggle Pin B Set Timer0 = 0

Phase shift controller setup