Generating 3-phase sine wave..

[sirvo]

Ok...

INCLUDE "DT_INTS-14.bas" ; Base Interrupt System
INCLUDE "ReEnterPBP.bas" ; Include if using PBP interrupts

'@ DEVICE pic16F777, HS_OSC ; System Clock Options
'@ DEVICE pic16F777, WDT_OFF ; Watchdog Timer
'@ DEVICE pic16F777, PWRT_ON ; Power-On Timer
'@ DEVICE pic16F777, MCLR_OFF ; Brown-Out Detect
'@ DEVICE pic16F777, PROTECT_OFF
@  __CONFIG    _CONFIG1, _MCLR_OFF & _PWRTE_ON & _WDT_OFF & _HS_OSC


define  OSC 20


DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive
DEFINE HSER_TXSTA 24h ' Enable transmit, BRGH = 1
DEFINE HSER_SPBRG 10  ' 115200 Baud @ 20MHz, -1,36%
DEFINE HSER_CLROERR 1 ' Clear overflow automatically

clear
MODO    VAR BYTE[3]
DIST    VAR BYTE
SAG     VAR BYTE[3]
SAG[0] = 0
SAG[1] = 0
SAG[2] = 0
SWELL   VAR BYTE
SWELL = 0

CTRL    VAR BYTE
LOAD    VAR WORD
RA      VAR BYTE
RB      VAR BYTE
RC      VAR BYTE
RD      VAR BYTE
RA = 0
RB = 1
RC = 0
RD = 0
V       VAR BYTE
VA      VAR BYTE
VB      VAR BYTE
VC      VAR BYTE
CONTA    VAR BYTE
CONTB    VAR BYTE
CONTC    VAR BYTE
CONT    VAR BYTE
INDEX   VAR BYTE
FLAG    VAR BYTE
X       VAR BYTE

FLAG = 0
CONTA = 0
CONTB = 23
CONTC = 47
modo[0] = 1
modo[1] = 1
modo[2] = 1
' Set CCPx pins to outputs
TRISC.2 = 0 ' CCP1 output
TRISC.1 = 0 ' CCP2 output (could also be assigned to RB3)
TRISB.5 = 0 ' CCP3 output
TRISC.7 = 1
TRISC.6 = 0
TRISD.0 = 0
' Set CCP modules to PWM mode
CCP1CON = %00001100 ' Mode select = PWM
CCP2CON = %00001100 ' Mode select = PWM
CCP3CON = %00001100 ' Mode select = PWM

INTCON = %11000000
LOAD = 65250' 4320Hz
'LOAD = 0
TMR1H = LOAD.HIGHBYTE
TMR1L = LOAD.LOWBYTE
T1CON = %00000001
PIE1.0 = 1
PR2 = 200
'PR2 = 62
PORTD.0 = 0
' Set TMR2 up for 1:1 prescale & turn it on
T2CON = %00000100 ' TMR2 ON 1:1 prescale
'T2CON = %00011100 ' TMR2 ON 1:1 prescale


ASM
INT_LIST macro ;IntSource, Label,    Type, ResetFlag?
    INT_Handler TMR1_INT, _Timer1,   PBP, yes 
    INT_Handler RX_INT,   _GetChar,  PBP, yes 
    INT_Handler TX_INT,   _SendChar, PBP, yes 
    endm
    INT_CREATE ; Creates the interrupt processor
ENDASM
@    INT_ENABLE  TMR1_INT   ; Habilita interrupção do TMR1 
@    INT_ENABLE  RX_INT     ;- enable the interrupt
@    INT_ENABLE  TX_INT     ;- enable the interrupt


MAIN: 
    IF FLAG = 1 THEN 
        PORTD.0 = 1 
        flag = 0 
        CONTA = CONTA + 1
        CONTB = CONTB + 1
        CONTC = CONTC + 1
        if contA = 71 then contA = 0
        if contB = 71 then contB = 0
        if contC = 71 then contC = 0
            
        index  = conta
        if RA.0 = 1 then 
            DIST = RB
            SAG[0] = RC
            MODO[0] = DIST
        ELSE
            DIST = MODO[0]
        ENDIF
        GOSUB tabela
        va = (v*(100-sag[0]))/100
        
        index  = contB
        if RA.1 = 1 then 
            DIST = RB
            SAG[1] = RC
            MODO[1] = DIST
        ELSE
            DIST = MODO[1]
        ENDIF
        GOSUB tabela
        vb = (v*(100-SAG[1]))/100
        
        index  = contC
        if RA.2 = 1 then 
            DIST = RB
            SAG[2] = RC
            MODO[2] = DIST
        ELSE
            DIST = MODO[2]
        ENDIF
        GOSUB tabela
        vc = (v*(100-SAG[2]))/100

        RA = 0
        GOSUB SAIDA
        PORTD.0 = 0 
    endif      
    GOTO MAIN

    
TABELA:
    SELECT CASE DIST
    CASE 1: ' Fundamental
           LOOKUP INDEX, [100,109,118,126,135,143,151,158,165,171,177,183,187,191,195,197,199,200,200,199,198,196,193,189,185,180,175,168,162,154,147,139,130,122,113,104,96,87,78,70,61,53,46,38,32,25,20,15,11,7,4,2,1,0,0,1,3,5,9,13,17,23,29,35,42,49,57,65,74,82,91], V 
    CASE 2: ' 3 com 20%
           LOOKUP INDEX, [100,114,127,140,152,162,170,177,182,185,187,187,187,185,184,182,181,180,180,180,181,182,184,185,187,187,187,185,182,177,170,162,152,140,127,114,100,86,73,60,48,38,30,23,18,15,13,13,13,15,16,18,19,20,20,20,19,18,16,15,13,13,13,15,18,23,30,38,48,60,73,86], v
    CASE 3: ' 3 com 20% + 5 com 10%
           LOOKUP INDEX, [100,118,135,150,161,170,175,178,178,178,177,177,178,180,182,185,188,189,190,189,188,185,182,180,178,177,177,178,178,178,175,170,161,150,135,118,100,82,65,50,39,30,25,22,22,22,23,23,22,20,18,15,12,11,10,11,12,15,18,20,22,23,23,22,22,22,25,30,39,50,65,82], V
    CASE 4: ' 3 com 20% + 5 com 10% + 7 com 10%
           LOOKUP INDEX, [100,124,144,159,168,171,170,168,168,171,175,181,187,190,190,188,184,181,180,181,184,188,190,190,187,181,175,171,168,168,170,171,168,159,144,124,100,76,56,41,32,29,30,32,32,29,25,19,13,10,10,12,16,19,20,19,16,12,10,10,13,19,25,29,32,32,30,29,32,41,56,76], V
    CASE 5: ' 5 com 10% + 7 com 20%
           lookup index, [100,122,139,149,151,147,141,136,137,145,157,172,186,194,197,194,188,183,181,183,188,194,197,194,186,172,157,145,137,136,141,147,151,149,139,122,100,78,61,51,49,53,60,64,63,55,43,28,14,6,3,6,12,17,19,17,12,6,3,6,14,28,43,55,63,64,59,53,49,51,61,78], v
    CASE 6:
           return
    CASE 7:
           return 
    end select
return

SAIDA:
        CCP1CON.4 = VA.0
        CCP1CON.5 = VA.1
        CCPR1L = VA >> 2
        CCP2CON.4 = VB.0
        CCP2CON.5 = VB.1
        CCPR2L = VB >> 2
        CCP3CON.4 = VC.0
        CCP3CON.5 = VC.1            
        CCPR3L = VC >> 2
RETURN
  
Timer1:
    TMR1H = load.highbyte 
    TMR1L = load.lowbyte              
    FLAG = 1 
@ INT_RETURN  

GetChar:
      HSERIN [dec RA] 
      HSERIN [dec RB]  
      HSERIN [dec RC]  
      HSERIN [dec RD]

@   INT_ENABLE  TX_INT     ;- enable the interrupt
@   INT_RETURN 

SendChar:
      'hserout [dec cod[0], "-", dec cod[1], "-", dec cod[2], "-", dec cod[3]]
@   INT_DISABLE  TX_INT    ;- disable the interrupt
@   INT_RETURN 

END

[Darrel Taylor]

Ah ha, there's the missing info.

With the lines ...

va = (v*(100-sag[0]))/100

I'm measuring each one at about 125us. There's 3 of them, so that's 375us, plus the 70us I measured for the main loop last time, for a total of around 450us.

Timer1 is overflowing every ~230us, so it's definately missing the Flag's.
<br>

[sirvo]

"Ah ha..."

Funny.. I'm trying to imagine the Eureka's face you had done...

Well, I kind of did not get it. You are saying that the program is wasting time at this statement?

 va = (v*(100-sag[0]))/100

Why would it be happening? 125us just to make 1 subtract, 1 mult and 1 div?

Thanks Darrel!

[Darrel Taylor]

Yup, multiplication and division takes a LOT of loops to do.

In this thread I had measured a single 16/16 divide at over 76us (382 instructions).

Keep in mind that in PBP, ALL mutiplications and divisions are done as a 16-bit operation. So even though the variables are BYTE's, it takes the same time as if they were WORD's.

I haven't timed a 16*16 multiply yet, but from these results I'd say it's probably just under 50us.

Time to find a new way to do the math.
<br>

[skimask]

Keep in mind that in PBP, ALL mutiplications and divisions are done as a 16-bit operation. So even though the variables are BYTE's, it takes the same time as if they were WORD's.

And if I remember right, ALL mult's and div's done with PBPL in 2.50B are done as signed-31-bit operations. So, now it's even 'worse'!
Sounds like it might be time for a small assembly routine for 8 and 16 bit math when speed counts...something like: @ mult16, @ mult8, @ div16, @ div8
I've been meaning to do it...sometime...when I get time...to save time...

[Darrel Taylor]

Sounds like it might be time for a small assembly routine for 8 and 16 bit math when speed counts...something like: @ mult16, @ mult8, @ div16, @ div8
I've been meaning to do it...sometime...when I get time...to save time...

That would be really handy. And if you do, here's a good place to start ...

PIC Microcontoller Basic Math Methods
http://www.piclist.com/techref/microchip/math/basic.htm
<br>

[sirvo]

Time to find a new way to do the math.
<br>

OR, increase timer1 interrupt and decrease the number of the sine table points..

However, I think that 71 points is on the edge for generating a good signal in this aplication. Reducing this number would not let the application to create good harmonics distortion due to the big step between these number...Well, all of this would be answered trying, right?

I'll get an osc. next thursday... until there I've got to wait...

Thanks again!

[Darrel Taylor]

sirvo> OR, increase timer1 interrupt and decrease the number of the sine table points..

Actually, I was thinking you should have a larger table at a faster rate.

But it'll take a few changes.
Here's a couple things that will help speed things up.

First, change the interrupt TYPE for TMR1_INT to ASM.
The handler only set's the flag and loads the timer, so it doesn't need to save all the PBP system registers. This should save about 40us.<hr>
Then if the SAG() values ranged from 0-255 instead of 0-100, this could replace what you had ...

        va = v */ (255-sag[0]+1)

It will save 75us each time, which brings the whole loop down to 220us. Just barely under the Timer1_INT period. But if you want to add more features, or increase the sin table, there won't be any time left.
<hr>
Going a bit further, here's a little asm routine that'll really help.

It Scales an 8-bit value to another 8-bit value.
Essentially it does Result=Value*(Scale+1), with the actual result being in the HighByte of the R2 variable.

With this you can do ...

;        va = (v*(100-sag[0]))/100
        R0 = V              ; Put the value in R0
        R1 = 255-SAG[0]     ; Inverted SAG to R1
        CALL Scale8         ; Scale R0*(R1+1)
        VA = R2.HighByte    ; result is in R2.HighByte

Here's the ASM part. Put it somewhere above the Main loop.

ASM ; ---- [Scale8 - Scale an 8-bit value]----------
;  Input:   R0 = Value to scale                    |
;           R1 = Scale (0-255)                     |
;  Output:  R2 = R0*(R1+1)                         |
;           Result is in  R2.HighByte              |
;---------------------------------------------------
    goto OverScale8
_Scale8
    clrf     R2          ; result LowWord
    clrf     R2 + 1      ; result HighWord
    movlw    8
    movwf    R3          ; Loop counter

    movf     R1, W       ; Load Scale in W reg
    bcf      STATUS, C   ; clear carry

Scale8Loop
    rrf      R0, F       ; Rotate the Value, lsb goes to carry
    btfsc    STATUS, C   ; if the carry = 1 then
    addwf    R2 + 1, F   ;   add Scale to result.highbyte
    rrf      R2 + 1, F   ; rotate the result.highbyte, lsb goes to carry
    rrf      R2, F       ; rotate carry into result.lowbyte
    decfsz   R3, F       ; next loop
    goto     Scale8Loop

    addwf    R2, F       ; add 1 more Scale
    btfsc    STATUS, C   ; if carry
    incf     R2 + 1, F   ; inc highbyte

    return

;----[Macro to make things easier]------------------
Scale8  macro Value, Scale, Bout
    MOVE?BB  Value, R0
    MOVE?BB  Scale, R1
    L?CALL   _Scale8
    MOVE?BB  R2 + 1, Bout
  endm

OverScale8
ENDASM ; ---- [End of Scale8]-----------------------

Using the above code, each call to Scale8 takes about 18us or 54us for all three. With 70us for the rest, it ends up doing the whole thing in about 125us. Well within the 230us periods. And time left over for a bigger/faster table.

I'm not using the macro at this point. It's just there for future reference.

Just remember ... SAG is 0-255 now. So if you need to convert it...

SAG(0) = SAG0value*255/100

Which is much like what you had in the beginning. But now it's only done when setting the SAG values, instead of 12000 times a second.

HTH,

[sirvo]

I'll try all of this as soon as possible...

Hey, Does 16LF777 work with @20Mhz? (LF)

In the datasheet DS30498C.pdf page 208, I see a graph showing that this Industrial model does not achieve the 20MHz frequency... Am I crazy?