How to start PIC16F676 ...??

[Ian Rogers]

Flashing approximately 90 times a second...

You dont need the 5k pullup..... inr MCLR is internal.

Eric changed the timings for simulation.... there is only 7mS delay.

 

[koolguy]

changing its value to .30 for more delay.!!!!

As i said i have changed it value to have more delay!!
please tell what does this .2 significance is that decimal no??

 

[ericgibbs]

As i said i have changed it value to have more delay!!
please tell what does this .2 significance is that decimal no??

hi,
Look at my Post #33 for the original 0.5Second delay times... .2 is decimal '2'

 

[koolguy]

OK, now my latest code which are working fine in oshon....

LIST p=16F676 ;tell assembler what chip we are using
include "P16F676.inc" ;include the defaults for the chip
__config 0x3D14 ;sets the configuration settings (oscillator type etc.)

errorlevel -302, -207

CounterA equ 0x20
CounterB equ 0x21
CounterC equ 0x22
CounterD equ 0x23

; HERE SET TO INTERNAL OSCILLATOR 4MHZ
ORG 0
GOTO INIT

INIT
bcf STATUS,RP0
clrf PORTA
MOVLW 0x05
MOVWF CMCON

BSF STATUS,RP0
clrf ANSEL ; disable ADC

movlw 0x0c
MOVWF TRISA ; porta as inp

clrf TRISC ; portc as out
BCF STATUS,RP0

START
call delay
movlw 0xff
movwf PORTC
call delay
clrf PORTC
GOTO START

;PIC Time Delay = 0.50000200 s with Osc = 4000000 Hz
delay: movlw D'3'
movwf CounterC
movlw D'138'
movwf CounterB
movlw D'85'
movwf CounterA
loop decfsz CounterA,1
goto loop
decfsz CounterB,1
goto loop
decfsz CounterC,1
goto loop
retlw 0

end

 

[ericgibbs]

hi Ritesh,
Its important to note that while the Delay periods are counting the PIC is 'tied up' doing just that.

If you want to experiment, consider using the PIC's internal counters to create Interrupts for these delays, it will leave the PIC free to do other tasks.

 

[Ian Rogers]

Perfect.. 500ms of 500ms on... Remember as well Ritesh! If you use internal 4mhz crystal to load the OSCCAL value ( last location of program memory ).

 

[koolguy]

Hi, the pic is working fine on board i find it easy then chip used before !!

 

[Ian Rogers]

Why which one did you use?

 

[koolguy]

Why which one did you use?

I mean to say chip like counters, astable vibrator now no tension of changing the chip, only code!

 

[koolguy]

Hi again,

After running LED program successfully i want to make a analog to digital program..please guide me how to do this??

 

[Ian Rogers]

Hi Ritesh....More specific? analogue to digital what?

 

[koolguy]

Hi again,

Hi Ritesh....More specific? analogue to digital what?

As i want to make PWM for this we will require to read R from pot. meter!!

 

[Ian Rogers]

Select a pic... You'll need a CCP module (PWM output) and an ADC input...

The smallest of these is the 8 pin pic12f1822 / 40 You can set up the 10 bit ADC to supply a 10 bit PWM signal. so input on pin 7 and output on pin 5.

You can do this very easy in Oshonsoft (I know you use this)


Oh sorry....... Not in Oshonsoft .... chip not supported. on of the pics will be though.

 

[Nigel Goodwin]

Select a pic... You'll need a CCP module (PWM output) and an ADC input...

Sorry, but you don't require an ADC - you can easily read a variable resistor on a standard pin, check my joystick tutorial!.

In many ways it's BETTER than an ADC for reading a pot.

 

[koolguy]

Select a pic... You'll need a CCP module (PWM output) and an ADC input...

I want to try it with PIC16F676

 

[Ian Rogers]

Sorry, but you don't require an ADC - you can easily read a variable resistor on a standard pin, check my joystick tutorial!.

In many ways it's BETTER than an ADC for reading a pot.

Ah... We used to do that for PC joysticks..... Simple AtoD but wasn't particularly linear.


Ritesh.. That chip hasn't got a PWM module so you'll have to make a software one.

 

[koolguy]

Ritesh.. That chip hasn't got a PWM module so you'll have to make a software one.

No problem, please tell the procedure.

 

[koolguy]

as it will help me to learn PWM from code!!

 

[Ian Rogers]

I did it yesterday...

#include<htc.h>
#define _XTAL_FREQ  4000000
__CONFIG(0x31C4);


int OnPulse = 128, OffPulse = 128;
char TOG = 0;

void interrupt ISR(void)
	{
	TOG = ~TOG;
	if(TOG)
		{
		TMR0 = OnPulse;
		RC0 = 1;
		}
	else
		{
		TMR0 = OffPulse;
		RC0 = 0;
		}	
	T0IF = 0;
	}

int ADC_Read()
	{
	ADCON0 = 1;
	__delay_ms(40);
	GO = 1;
	while(GO);
	return ADRESH;
	}

void main()
	{
	int pulse;
	TRISC = 0;
	TRISA = 255;
	CMCON = 7;
	TMR0 = OnPulse;
	ADCON0 = 0x0;
	ADCON1 = 0x50;
	ANSEL = 0x1;
	OPTION_REG = 0;
	T0IE = 1;
	GIE = 1;
	while(1)
		{
		pulse = ADC_Read();
		OnPulse = pulse;
		OffPulse = 255 - OnPulse;		
		}

	}

8bit PWM at 2khz

 

[koolguy]

Can't we do this in assembly??
and please explain this..

8bit PWM