6 HPWM signal generation with PIC18F4431

[pxidr84]

Okay, I've a little bit modified the Bruce's program.
It runs well in ISIS Proteus with my defined duty cycles, and all of the 6 PWM outputs works.

But there is a little problem :


As you can see, U and W phases are working properly, but not the V phase (the low-side PWM is not inverted like the others).

Here's my modified code :

DEFINE LOADER_USED 1
DEFINE OSC 20
    
    ' At 20MHz, to figure a PWM frequency of 19.455kHz
    ' TPWM = time period of PWM frequency
    ' PTPER = 12-bit period register PTPERL and PTPERH
    ' PTMRPS = PWM time base prescaler
    ' 
    '        (PTPER+1)*PTMRPS  257
    ' TPWM = ----------------  =  ------------ = 0.0000514 
    '             Fosc/4            5000000
    '
    ' Frequency = 1/TPWM = 1/0.0000514 = 19.455kHz
    '
    ' PWM resolution (bits resolution for duty cycle)
    '
    '              log(20MHz/19.455kHz)    3.01
    ' Resolution = ------------------ = ----------- = 10 bits
    '                    .301              .301
      
    ' so we'll need a word sized var for Duty
uduty VAR WORD
vduty VAR WORD
wduty VAR WORD
   
    PORTB = 0               ' clear port latch
    TRISB = %11000000       ' PWM0,1,2,3,4,5 outputs
    
    TRISC = 2         ' RC1 = FLTA input (ground RC1 to halt PWM)
                            ' RC1 should be pulled high for normal PWM operation
                            ' when fault A is enabled.
    ' PCPWM init
    DTCON = %00000101       ' ~500nS dead-time (for complementary outputs only)
    PTCON0 = %00000100      ' 1:1 postscale, Fosc/4 1:1 prescale, free running mode
                            ' PTCON0 = %00000100 would give 19.45kHz/4
    PTPERL = 0              ' 
    PTPERH = 1              ' PTPER = $0100 or 256d for ~19.45kHz
	
    ' PWM4,5 independent, PWM0,1,2,3 complementary
    PWMCON0 = %01010100     ' PWM[5:0] outputs enabled
    PWMCON1 = 1             ' updates enabled, overrides sync w/timebase
    PTCON1 = %10000000      ' PWM time base is ON, counts up
    FLTCONFIG = %00000011   ' enable fault A, cycle-by-cycle mode


'Phases duty test
uduty = 800              ' ~50%
vduty = 500
wduty = 300
        
pwmlp: ' PWM update loop

'PWM U phase 
PDC0L = uduty.LowByte
PDC0H = uduty.HighByte

'PWM V phase
PDC1L = vduty.LowByte
PDC1H = vduty.HighByte

'PWM W phase  
PDC2L = wduty.LowByte
PDC2H = wduty.HighByte

goto pwmlp

Thanks in advance for any advice.