sinusoidal PWM

[ScaleRobotics]

Great!

Yes, that is the duty cycle. Why not modify your array for the 90% instead of doing math here? We want to keep multiplication out of our assembly interrupt handler, otherwise, we will need to change it to a PBP type interrupt. And that would take a lot of time for each interrupt, as it needs to save and restore 70 registers each time it interrupts. If you need it to change dynamically, the beauty of an array rather than a lookup, is that you can change it on the fly (doing math in your main).

[bwaxing]

Thanks, i think i got it...let me experiment with the code i have and see what i got.....
thank again..

[bwaxing]

hellow everyone,

I'm simulating this code on proteus Isis but m not getting the expected waveform(sinusoidal wave form)....the code compiles successful...but the waveform i'm getting getting on the scope is not the one...i need help please..

;
define OSC 20

;*****************VARIABLE DECLARATION******************************************
wsave   VAR BYTE    $70     SYSTEM      ' alternate save location for W 
wsave1  VAR BYTE    $A0     SYSTEM      ' location for W if in bank1
wsave2  VAR BYTE    $120    SYSTEM      ' location for W if in bank2
wsave3  VAR BYTE    $1A0    SYSTEM      ' location for W if in bank3
STEPCOUNT var byte                      'Define stepcount as byte type variable
stepcount = 256

;**************SETTING THE REGISTERS WITH APPROPIATE BIT DEFINITION************* 
ADCON0 = %00000000
ADCON1 = %00000000  ;all anolog output
trisb = %11111111   ;define porta as input
trisc = %11111011   ;make ccp1/portc.2 an output pin
trisa = %11111111   ;define porta as input
TMR2 = 16
PR2 = 34           ;set for 36Khz HPWM(=72 steps*10 times*50hz)        
CCP1CON = %000001100       ;set to pwm mode
T2CON=%00000110           ;enable timer2 and set timer2 prescaler value of 1:4

;****************A sine lookup table in an array********************************
sineval var byte[72]
sineval[1] = 128      ;0 degree
sineval[2] = 137      ;5 degree
sineval[3] = 146
sineval[4] = 154
sineval[5] = 163
sineval[6] = 171
sineval[7] = 179
sineval[8] = 187
sineval[9] = 194
sineval[10] = 200
sineval[11] = 206
sineval[12] = 212
sineval[13] = 216
sineval[14] = 220
sineval[15] = 224
sineval[16] = 227
sineval[17] = 228
sineval[18] = 229
sineval[19] = 230     ;90 degree
sineval[20] = 229
sineval[21] = 228
sineval[22] = 227
sineval[23] = 224
sineval[24] = 220
sineval[25] = 216
sineval[26] = 212
sineval[27] = 206
sineval[28] = 200
sineval[29] = 194
sineval[30] = 187
sineval[31] = 179
sineval[32] = 171
sineval[33] = 163
sineval[34] = 154
sineval[35] = 146
sineval[36] = 137
sineval[37] = 128  ;180 degree
sineval[38] = 119
sineval[39] = 110
sineval[40] = 102
sineval[41] = 93
sineval[42] = 85
sineval[43] = 77
sineval[44] = 69
sineval[45] = 62
sineval[46] = 56
sineval[47] = 50
sineval[48] = 44
sineval[49] = 40
sineval[50] = 36
sineval[51] = 32
sineval[52] = 29
sineval[53] = 28
sineval[54] = 26
sineval[55] = 26
sineval[56] = 26
sineval[57] = 28
sineval[58] = 29
sineval[59] = 32
sineval[60] = 36
sineval[61] = 40
sineval[62] = 44
sineval[63] = 50
sineval[64] = 56
sineval[65] = 62
sineval[66] = 69
sineval[67] = 77
sineval[68] = 85
sineval[69] = 93
sineval[70] = 102
sineval[71] = 110
sineval[72] =119
 
timerone var word 
 
INCLUDE "DT_INTS-14.bas"     ; Base Interrupt System

;********Define INT_Handler as ISR********************************************** 
ASM
 
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   TMR1_INT,   _sine,   ASM,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

T1CON = $31    ; Prescaler = 8, TMR1ON          
TMR1L = 255    
TMR1H = 254
@   INT_ENABLE  TMR1_INT     ; Enable Timer 1 Interrupts  
timerone = $EE16           ;gives about 50 hz sine 
Main:
        pause 5
        'if timerone = $F9FF then timerone = $FF00
 
GOTO Main
 
'---[TMR1_INT - interrupt handler]------------------------------------------
 
sine:
    TMR1L = timerone.byte0
    TMR1H = timerone.byte1     
    CCPR1L = sineval[STEPCOUNT]>>1 
    stepcount = stepcount -1
    if stepcount = 0 then stepcount = 72
@    INT_RETURN

simulation results attached

[ScaleRobotics]

I don't see any kind of wave form on the scope???

[bwaxing]

sure,it is just a line and not a sine wave form as expected....the simulation log say there are attempts to read unimplemented memory locations being ignored..i dont know what does that mean and if it may be one of the cause...i need help.

[walter]

Maybe it is complaining that you have set your array to:
sineval var byte[72]

and then you go from 1 to 72.

You either need to change it to 0 to 71, or change your array size to 73

[bwaxing]

i have changed the number of array size together with other modifications but there is no change in the simulation result,it is still a line....

define OSC 20
 
;*****************VARIABLE DECLARATION******************************************
wsave   VAR BYTE    $70     SYSTEM      ' alternate save location for W 
wsave1  VAR BYTE    $A0     SYSTEM      ' location for W if in bank1
wsave2  VAR BYTE    $120    SYSTEM      ' location for W if in bank2
wsave3  VAR BYTE    $1A0    SYSTEM      ' location for W if in bank3
STEPCOUNT var byte                      'Define stepcount as byte type variable
stepcount = 256
 
;**************SETTING THE REGISTERS WITH APPROPIATE BIT DEFINITION************* 
ADCON0 = %00000000
ADCON1 = %00000000  ;all anolog output
trisb = %11111111   ;define porta as input
trisc = %11111011   ;make ccp1/portc.2 an output pin
trisa = %11111111   ;define porta as input
TMR2 = 16
PR2 = 34           ;set for 36Khz HPWM(=72 steps*10 times*50hz)        
CCP1CON = %000001100       ;set to pwm mode
T2CON=%00000110           ;enable timer2 and set timer2 prescaler value of 1:4
 
;****************A sine lookup table in an array********************************
sineval var byte[73]
sineval[1] = 128      ;0 degree
sineval[2] = 137      ;5 degree
sineval[3] = 146
sineval[4] = 154
sineval[5] = 163
sineval[6] = 171
sineval[7] = 179
sineval[8] = 187
sineval[9] = 194
sineval[10] = 200
sineval[11] = 206
sineval[12] = 212
sineval[13] = 216
sineval[14] = 220
sineval[15] = 224
sineval[16] = 227
sineval[17] = 228
sineval[18] = 229
sineval[19] = 230     ;90 degree
sineval[20] = 229
sineval[21] = 228
sineval[22] = 227
sineval[23] = 224
sineval[24] = 220
sineval[25] = 216
sineval[26] = 212
sineval[27] = 206
sineval[28] = 200
sineval[29] = 194
sineval[30] = 187
sineval[31] = 179
sineval[32] = 171
sineval[33] = 163
sineval[34] = 154
sineval[35] = 146
sineval[36] = 137
sineval[37] = 128  ;180 degree
sineval[38] = 119
sineval[39] = 110
sineval[40] = 102
sineval[41] = 93
sineval[42] = 85
sineval[43] = 77
sineval[44] = 69
sineval[45] = 62
sineval[46] = 56
sineval[47] = 50
sineval[48] = 44
sineval[49] = 40
sineval[50] = 36
sineval[51] = 32
sineval[52] = 29
sineval[53] = 28
sineval[54] = 26
sineval[55] = 26
sineval[56] = 26
sineval[57] = 28
sineval[58] = 29
sineval[59] = 32
sineval[60] = 36
sineval[61] = 40
sineval[62] = 44
sineval[63] = 50
sineval[64] = 56
sineval[65] = 62
sineval[66] = 69
sineval[67] = 77
sineval[68] = 85
sineval[69] = 93
sineval[70] = 102
sineval[71] = 110
sineval[72] =119
 
timerone var word 
 
INCLUDE "DT_INTS-14.bas"     ; Base Interrupt System
 
;********Define INT_Handler as ISR********************************************** 
ASM
 
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   TMR1_INT,   _sine,   ASM,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM
 
T1CON = $31    ; Prescaler = 8, TMR1ON          
TMR1L = 255    
TMR1H = 254
@   INT_ENABLE  TMR1_INT     ; Enable Timer 1 Interrupts  
timerone = $EE16           ;gives about 50 hz sine 
Main:
        pause 5
        'if timerone = $F9FF then timerone = $FF00
 
GOTO Main
 
'---[TMR1_INT - interrupt handler]------------------------------------------
 
sine:
    TMR1L = timerone.byte0
    TMR1H = timerone.byte1     
    CCPR1L = sineval[STEPCOUNT]>>1 
    stepcount = stepcount -1
    if stepcount = 1 then stepcount = 73
@    INT_RETURN