can anyone help me...

[kvrajasekar]

Hi Darrel,

Thanks lot,
Plz tell me, why u select FOSC32,whynot FOSC8.

and my final ques is how to find the rising edge(tON) and Falling Edge(tOFF).I used the following code to find this,
This is a digital i/p,
go_vol1
btfss PORTB,0 ;checking whether porta pin is set or not
goto go_vol1 ;waiting
clrf TMR0
Duty_vol1
btfsc PORTB,0 ;keep monitoring rising edge
goto Duty_vol1
movf TMR0,0
movwf volt_val

Plz give me ur suggestion to use this code,If it is correct my work will get finish.

And also i m using LCD interface.wat should be the minimum delay b/w the commands to LCD.

-thanks.

[Darrel Taylor]

Hi Darrel,

Thanks lot,
Plz tell me, why u select FOSC32,whynot FOSC8.

I chose FOSC32 because I didn't know what crystal you were using.
If you had a 20mhz crystal FOSC8 would probably not work.
But even with a 4mhz crystal, FOSC32 will still work fine.

and my final ques is how to find the rising edge(tON) and Falling Edge(tOFF).I used the following code to find this,
This is a digital i/p,
go_vol1
btfss PORTB,0 ;checking whether porta pin is set or not
goto go_vol1 ;waiting
clrf TMR0
Duty_vol1
btfsc PORTB,0 ;keep monitoring rising edge
goto Duty_vol1
movf TMR0,0
movwf volt_val

Plz give me ur suggestion to use this code,If it is correct my work will get finish.

The code shown will wait for a rising edge, then measure the duration of the high pulse. if you add the same thing again for the low pulse, you'll have both values.

go_vol1
		btfss 	PORTB,0   ; Wait for rising edge 
		goto 	go_vol1
		clrf	TMR0      ; clear TMR0 for high pulse
Duty_vol1
		btfsc	PORTB,0	  ; keep monitoring high pulse
		goto	Duty_vol1
		movf	TMR0,0    ; put TMR0 value in W reg
		clrf    TMR0      ; clear TMR0 for low pulse
		movwf	tON       ; save timer value to variable

Duty_vol2
		btfss	PORTB,0	  ; keep monitoring low pulse
		goto	Duty_vol2
		movf	TMR0,0    ; put TMR0 value in W reg
		movwf	tOFF      ; save timer value to variable

> And also i m using LCD interface.wat should be the minimum delay b/w the commands to LCD.

It varies from display to display. I think the average is around 1.6ms, but some are as high as 2.5ms for commands. 2.0ms is standard with 50us DATA delay.

hth,

[kvrajasekar]

Thanks lot Darrel,I m very happy to see ur reply.

can i use the same codings for zerocrossing?bcoz zero crossing will occur every rising or falling edge.plz correct me if i am wrong?

[Darrel Taylor]

No I'm sorry, but you said the last one was your "Final Question".

Ok, 1 more.

If you're waiting for a zero-cross, then you probably don't need to time the event with TMR0.

Wait4ZeroCross                    ; Wait for zero-cross, up or down
    btfss   PORTB,0
    goto    WaitForHigh
WaitForLow
    btfsc   PORTB,0
    goto    WaitForLow
    goto    ZeroCrossDone
WaitForHigh
    btfss   PORTB,0
    goto    WaitForHigh
ZeroCrossDone

[kvrajasekar]

Thank you very much Mr.Darrel.

[sougata]

In a UPS (Offline I suppose) control your primary task would be to monitor mains for abnormality which includes under/over voltage, blackout/brownout. I suggest sampling the mains voltage at 0.5ms intervals. Also a premature zero-cross is a definite indication of mains failure. While I use PORTB.0 INT for the zero cross in asm you may use Instant Interrupt to make your life easier.

http://www.picbasic.co.uk/forum/showthread.php?t=3251

[kvrajasekar]

Hi sougata,

I m using power failure indication for UPS,wen it detects,i should start the inverter,also wen power resumption occur i should turn off the inverter and start with main.

How can acheive this task,plz give ur ideas to implement,I m using PIC16f72.

I am waiting for ur reply.