using pwm to generate pure sine wave

[kit_714]

pwm 8051

Hi All,

may i ask can AT89S52 generate 3 PWMs simutaneously? As i need to interface the RGB LED projects and need to use PWM to control the color of LEDs...

Thanks and regards,

Andy

 

[aomran]

8051 pwm

hay andy..
would you please send more information, but any how you may use its internal timer to generate any required PWM signal


Thanks
Ahmed

 

[kit_714]

pwm in 8051

Hi All,

The question is....

Can i generate 3 PWM at the same time using internal timer of AT89s52?

Thanks a lot!!

Andy

 

[svicent]

pwm using 8051

Andy, the article "Balancing D/A Conversion on One Pin", Circuit Cellar #140 March 2002, contains code to generate eight PWM outputs using the timer T0 interrupt.

 

[aomran]

8051 pwm code

Hay Andy,
yes you can generate 3 PWM using 8952 internal timer, just send me the PWM details (period,duty) and i can send you sample code......




Thanks
Ahmed

 

[davidgrm]

pwm with 8051

Also check out the 8051FA - Can do PWM in harware

 

[shri2384]

pwm for 8051

HI , I AM GENERATING PWM USING 8051 FOR 230 VOLTS 50HZ SINE WAVE OUTPUT THROUGH PURE SINE WAVE INVERTER. I AM DRIVING MOSFETS THROUGH PWM.I USED 20MS TOTAL TIME PERIOD FOR 50HZ AND SET/CLR PORT PINS

 

[myid123456]

generating sinewave using 8051 timer

ok why dont you give your code for others to learn?

 

[svicent]

c code to generate a pwm

EIGHT PWM OUTPUTS USING PORT P1 AND TIMER T0
(From Circuit Cellar #140)

Suppose that timer T0 is working in 16-bit mode and requests an interrupt
when it overflows (passes from 0xFFFF to 0x0000). The interrupt service
routine recharges the timer T0 with 0xFE00 so that a new interrupt takes
place after 512 machine cycles. The low part of the TL0 is not recharged
to obtain more precision.

PR_INTE_T0_PWM SEGMENT CODE
DT_PWM SEGMENT DATA
PUBLIC V
PUBLIC COUNTER

RSEG DT_PWM
COUNTER: DS 1 ;unsigned char COUNTER
V: DS 8 ;unsigned char V[8]

CSEG AT 0000BH ;T0 interrupt vector
LJMP INTE_T0

RSEG PR_INTE_T0_PWM

INTE_T0:
PUSH ACC
PUSH PSW
MOV PSW,#08H ;use register bank 1
MOV TH0,#0FEH ;interrupt after 512 cycles
INC COUNTER
MOV R0,#LOW (V) ;R0 point to V[0]
MOV R1,#00H
MOV R2,#08H ;repeat eight times
LABEL_01:
MOV A,@R0 ;ACC = VALUE
CJNE A,COUNTER,LABEL_02 ;CY = 0 if VALUE >= COUNTER
SETB C ;CY = 1 if VALUE = COUNTER
LABEL_02:
CPL C ;CY = 1 while VALUE > COUNTER
MOV A,R1
RRC A ;rotate right through carry bit
MOV R1,A ;move CY to R1.7
INC R0
DJNZ R2,LABEL_01
MOV P1,R1 ;refresh PWM outputs
POP PSW
POP ACC
RETI

 

[homik52]

Re: pwm for 8051

can u please give me the circuit diagram of pure sine inverter and its whole explanation?

 

[humayun8khan]

Re: pwm for 8051

shri can you please share the code here please.

 

[humayun8khan]

whats wrong with this code ..can any one help...



#include <p18cxxx.h>
#include <delays.h>

#pragma config OSC = HS /* Sets the oscillator mode to HS */
#pragma config WDT = OFF /* Turns the watchdog timer off */
#pragma config LVP = OFF /* Turns low voltage programming off */
#pragma config DEBUG = OFF /* Compiles without extra debug code */
//LCD Control pins




const unsigned char sinetable[10] = {0,77,147,202,237,250,237,202,147,77};
int i=0;




void main(void)
{
TRISC=0xFB;
LATC=0;

CCP1CON=0x0C;
PR2=234;
T2CON=0x00;

while(1)
{
i=0;


for(i=0; i < 10; i++)
{
CCPR1L= sinetable;
TMR2=0x0;
PIR1bits.TMR2IF=0;
T2CONbits.TMR2ON=1;
while(PIR1bits.TMR2IF ==0);
}
}
}