PicKit2

[Jon Chandler]

Those are the "cut and paste" programmers 3v0. No effort to understand the code, just paste it in and be mystified when it doesn't work.

 

[3v0]

If C is taught properly it is an easily understood language. It can be as simplistic as this:

// blink LED on RA0
void delay(void)
{
          int i = 1000;  // i is a 16 bit integer value
    LOOP2:   
          i = i - 1;
          if (i > 0) goto LOOP2;
}
        
void main(void)
{
          LATA=0xFE; // RA0 is output
   LOOP1:
          PORTAbits.RA0 = 0;  // set RA0 to 0
          delay();            // call delay
          PORTAbits.RA0 = 1;  // set RA0 to 1
          delay();            // call delay
          goto LOOP1;
}

I do not suggest that we revert back to goto's but it might be a bit of a shock to some that it exists.

For the most part C code is what the author makes it. Anything for pure elegance to mud ugly.

 

[be80be]

I like this better less coding

void main (){
//ANSEL = 0;
PORTA = 0;                 // Initialize PORTA
TRISA = 0;                 // Configure PORTA as output
while(1){
  Delay_Ms(500);
  PORTA.B0 = ~PORTA.B0;
 }
}

 

[3v0]

I am sure most sane people would. The point of the code was stark simplicity. To illustrate that C code can be written that is easy to understand.

For the most part C code is what the author makes it. Anything for pure elegance to mud ugly.

Pst: Maybe you want to change this line:

PORTA.B0 = ~PORTA.B0;

 

[nomdomokunnom]

I have a feeling this is a dumb question, but I've finally gotten together the components and built the circuit suggested by 80be80, and MPLAB IDE is indicating that it's successfully finding and programming the target with a sample program I'm using (adapted from one of Nigel Goodwin's tutorials), but as hard as I try, I can't get the program to run. I tried running the debugger in MPLAB IDE but it's not recognising the chip (a 16F628A) in debugger mode and failing to enter it. Do I need to do something special to get the program to run on the chip? How do I run it independently of the programmer? Unfortunately I don't have a 5V supply other than through the programmer so I haven't been able to try simply powering it independently and disconnecting the programmer.

The test program oscillates output of both port A and B high and low at a frequency of ~4Hz, and I'm testing it by connecting an LED + series resistor between RA0 and Vdd (or between RA0 and Vss, neither work). Am I missing something obvious?

 

[Diver300]

Post your code. Without that, you'll get nothing, or wild guesses.

 

[nomdomokunnom]

Post your code. Without that, you'll get nothing, or wild guesses.

Thanks for the response; the code works, I've tried it with a different programmer (+ pre-assembled demo board) previously. The issue appears to be that the program isn't running. Here it is though:

;Hello chip program, adapted from http://www.winpicprog.co.uk/pic_tutorial1.htm.

	LIST	p=16F628a		;tell assembler what chip we are using
	include "P16F628A.INC"		;include the defaults for the chip
	__config _BODEN_ON & _CP_OFF & _DATA_CP_OFF & _PWRTE_ON & _WDT_OFF & _LVP_OFF & _MCLRE_ON & _XT_OSC

	cblock 	0x20 			;start of general purpose registers
		count1 			;used in delay routine
		counta 			;used in delay routine 
		countb 			;used in delay routine
	endc
	
	org	0x0000			;org sets the origin, 0x0000 for the 16F628,
					;this is where the program starts running	
	movlw	0x07
	movwf	CMCON			;turn comparators off (make it like a 16F84)

   	bsf 	STATUS,		RP0	;select bank 1
   	movlw 	b'00000000'		;set PortB all outputs
   	movwf 	TRISB
	movwf	TRISA			;set PortA all outputs
	bcf	STATUS,		RP0	;select bank 0

Loop	
	movlw	0xff
	movwf	PORTA			;set all bits on
	movwf	PORTB
	nop				;the nop's make up the time taken by the goto
	nop				;giving a square wave output
	call	Delay			;this waits for a while!
	movlw	0x00
	movwf	PORTA
	movwf	PORTB			;set all bits off
	call	Delay
	goto	Loop			;go back and do it again

Delay	movlw	d'250'			;delay 250 ms (4 MHz clock)
	movwf	count1
d1	movlw	0xC7
	movwf	counta
	movlw	0x01
	movwf	countb
Delay_0
	decfsz	counta,f
	goto	$+2
	decfsz	countb,f
	goto	Delay_0

	decfsz	count1,f
	goto	d1
	retlw	0x00

	end

 

[Diver300]

	__config _BODEN_ON & _CP_OFF & _DATA_CP_OFF & _PWRTE_ON & _WDT_OFF & _LVP_OFF & _MCLRE_ON [B]& _XT_OSC[/B]

You need INTRC oscillator mode if you don't have any external components.

 

[nomdomokunnom]

You need INTRC oscillator mode if you don't have any external components.

Thanks, I hadn't delved into trying to understand the config options yet, but that makes sense. It works now that I changed it to INTOSC_OSC_NOCLKOUT; thanks again.

 

[be80be]

If you use mplab to program you'll also have to release from reset to and change your fuse like Driver said

__CONFIG   _CP_OFF & _DATA_CP_OFF & _LVP_OFF & _BOREN_OFF & _MCLRE_ON & _WDT_OFF & _PWRTE_ON & _INTOSC_OSC_NOCLKOUT