Changing the sines frequency?

[pxidr84]

Unfortuntely, it doesn't works.

The problem is that TimerReload variable overwrites TimerReload EXT constant, defined later in DT routine.

' PIC initialization
DEFINE OSC 40      
DEFINE LCD_DREG PORTC
DEFINE LCD_EREG PORTD
DEFINE LCD_RSREG PORTD
DEFINE LCD_EBIT 0
DEFINE LCD_RSBIT 1
DEFINE LCD_COMMANDUS 4000
DEFINE LCD_DATAUS 1000


' BAS includes
INCLUDE "DT_INTS-18.bas"
INCLUDE "ReEnterPBP-18.bas"
INCLUDE "Sine_table.bas"


' Port registers configuration
TRISB=%11000000   ' PWM 0,1,2,3,4,5 outputs
TRISC=%00110000   ' +/- buttons


' PCPWM registers configuration
DTCON=%110        ' Deadtime (600ns)
PTCON0=%0         ' 1:1 postscale, Fosc/4 1:1 prescale, free running mode
PTCON1=%10000000  ' PWM time base is ON, counts up, 19.45kHz/4
PWMCON0=%1000000  ' PWM 0,1,2,3,4,5 set in pair mode
PWMCON1=%1        ' PWM timer sync configuration


' PWM calculation variables
ustep var byte
vstep var byte
wstep var byte
uduty var word
vduty var word
wduty var word
amplitude var word
carrier VAR word
flag var bit


' Variables definition
ustep=90          ' 360 degrees phase angle
vstep=60          ' 240 degrees phase angle
wstep=30          ' 120 degrees phase angle
amplitude=65535   ' Sinewave amplitude adjust (65535=max amplitude)
carrier=1023      ' Carrier frequency adjust (1023=13kHz)
flag=%0           ' Menu flag


' PWM carrier frequency register configuration
PTPERL=carrier.lowbyte  
PTPERH=carrier.highbyte

Dummy VAR WORD
Dummy2 VAR WORD
Dummy3 VAR WORD
ReloadInstruction VAR BYTE
TimerReload VAR WORD
Frequency VAR WORD


ReloadInstruction = 0  'Number of instructioncycles it takes to actually reload the timer. I don't know how many it is in this case. Tune later.

'For 40Mhz operation and 1:1 prescaler the timer ticks at 10Mhz
Dummy2 = 10000     'These can not be constants because 
Dummy3 = 10000     'constants doesn't work with DIV32

Frequency = 5000    'Lowest possible frequency is ~153Hz. Don't go below that.

Dummy = Dummy2 * Dummy3        'Intermediate result is now 10.000.000
TimerReload = DIV32 Frequency       'Divide 10.000.000 in Frequency (200 in this case) 
TimerReload = 65535 - TimerReload + 1 + ReloadInstruction  ' =15536 for 200Hz


' Interrupt processors 
ASM
INT_LIST macro
INT_Handler TMR1_INT,ReloadTMR1,ASM,no
INT_Handler TMR1_INT,_pwmint,PBP,yes
endm
INT_CREATE       
ENDASM

    
' Timers configuration
@Freq=4050   
@Prescaler=1                  
T1CON=$00


' Interrupts enable
@INT_ENABLE TMR1_INT
GOSUB StartTimer 


' Main program loop
mainlp:

' Debug display
if flag=0 then
LCDOUT $FE,$2,"Freq. adjust :"
LCDOUT $FE,$C0, DEC frequency
if PORTC.4=1 then frequency=frequency-1
if PORTC.5=1 then frequency=frequency+1
IF PORTC.4 AND PORTC.5=1 then flag=%1
else
LCDOUT $FE,$2,"Amp. adjust :"
LCDOUT $FE,$C0,DEC4 amplitude
if PORTC.4=1 then amplitude=amplitude-1
if PORTC.5=1 then amplitude=amplitude+1
endif

goto mainlp


' PWM calculation and update interrupt (Timer 1) 
pwmint:

' PWM U phase calculation
uduty=sine[ustep]
uduty=uduty<<4**amplitude

' PWM V phase calculation
vduty=sine[vstep]
vduty=vduty<<4**amplitude

' PWM W phase calculation
wduty=sine[wstep]
wduty=wduty<<4**amplitude

' PWM U, V and W update
PDC0L=uduty.lowbyte
PDC0H=uduty.highbyte
PDC1L=vduty.lowbyte
PDC1H=vduty.highbyte
PDC2L=wduty.lowbyte
PDC2H=wduty.highbyte

' Phase angle calculation
ustep=ustep-1
vstep=vstep-1
wstep=wstep-1

' Phase angle reinitialization
if ustep=0 then ustep=90
if vstep=0 then vstep=90
if wstep=0 then wstep=90

@INT_RETURN


' Timer1 interrupt handler
ASM                               
ReloadInst=8                  
MaxCount=65536+(ReloadInst/Prescaler)
TimerReload=MaxCount-(OSC*1000000/4/Prescaler/Freq)
ENDASM


' Timer1 variables
@Timer1=TMR1L                   
Timer1 VAR WORD EXT
'TimerReload VAR EXT              
TMR1ON VAR T1CON.0        


' Timer1 reload
ASM
ReloadTMR1
MOVE?CT 0,T1CON,TMR1ON     
MOVLW LOW(TimerReload)    
ADDWF TMR1L,F             
BTFSC STATUS,C             
INCF TMR1H,F           
MOVLW HIGH(TimerReload)   
ADDWF TMR1H,F             
MOVE?CT 1,T1CON,TMR1ON     
INT_RETURN
ENDASM


' Timer1 start/stop control
StartTimer:
Timer1=TimerReload         
TMR1ON=1                    
RETURN

StopTimer:
TMR1ON=0                 
RETURN