PIC12f629 LED Not Lighting Using XC8 MPLAB X, Microbrn, K150 Programmer

Welcome to the frustrating world of pic, nice to have you.

You have set the GP0 output to 1, but first you need to set the GP0 pin to be an output.
This can be done by setting the appropriate bit in the TRISIO register to 0.

So your code will look something like:


[code lang="c"]
#include

void main(){

//init GPIO pins
TRISIO = 0b00001000; // All GPIO pins as outputs (except GPIO3)
GPIO = 0b00000000; // Set all GPIO pins low
while(1){
GP0 = 1; // Set GP0 pin high
}

}[/code]

Refer to the header file at ...microchipxc8v1.10docspic12f629.h and the datasheet for more info.

Hope this helps.

Regards,

Sean

Sean, thanks for the reply. I just tried making your changes and it still will not turn the LED on. I've verified that the LED is working properly by hooking up a jumper from the + rail on my breadboard to the LED's +.

Any other reasons you can think of why this wouldn't work?

I'm starting to think my compiler isn't working properly.

I'm new to microcontrollers and am using MPLAB X with the XC8 compiler to write C code for a pic12f629. I am using microbrn and a pic k150 to program the pic.

Just trying to light an LED right now using GP0.

[code lang="c"]
#include


void main(){

while(1){
GP0 = 1;
}

}
[/code]

No matter what I try, I cannot get the LED to light up. I did download a hex file that makes the led flash and I was able to use microbrn to program the device and it worked.

Could I have a compilation issue? What could be causing this issue?

Try this:


[code lang="c"]#include

void main(){

//init GPIO pins
TRISIO = 0b00001000; // All GPIO pins as outputs (except GPIO3)
ANSEL = 0b00000000; // All GPIO are digital I/O
CMCON = 0b00000111; // Disable comparator
GPIO = 0b00000000; // Set all GPIO pins low

while(1){
GP0 = 1; // Set GP0 pin high
}
}[/code]


~ Raj

ANSEL = 0b00000000; throws a compilation error.

removing this line and compiling leads to the same results as I've been having. (the light doesn't turn on)

Does that work for you?

What does the compiler say when you put ANSEL = 0x00;
Do you get any error message?

Hi Geof you also need to load the oscall calibation value and make a note of what this is See the following link for details


http://picprojects.org.uk/projects/piccal.htm


The number of people who get caught out on this one is phenominal it can also produce some very strange effects especially if you dont read the chip fisrt before writing to this device

NB !!!
Always read this chip first before attemting to write any software to this device

Rajendra, thanks for the reply. I will work on it this weekend and let you know the results.

Thanks, Mark. I will work on it this weekend and get back to you.

Why dont you change the IDE you are working on with?
Try MikroC Pro for PIC.
I have written a small code in MikroC & it is working perfectly.
I am Attaching the design file which is in Proteus & the C code which has been written in MikroC & the Hex file.
Hope it Helps!

The compilation error is "undefined identifier ANSEL"

Mark, I added the OSCCAL value and still, the LED will not illuminate.

Thanks

If in doubt do it in assembler thats what I do when you get these errors so as to test the Ic Could be a port failure some times happens which pin of the port are you using to drive the led

You need to be carefull with this device as one of the port pins is input only under certain configurations

See datasheet quote ....

"_The exception is GP3, which is input only and its
TRISIO bit will always read as ‘1’ _"

An input change on GPIO change sets the GPIF
(INTCON) bit. The interrupt can be enabled/
disabled by setting/clearing the GPIE (INTCON)
bit. Plus individual pins can be configured through the IOC register.


Did you make this all digital output also try to reinstall mplab ide use MPlab ver 8.7 I’ve had problems with MPLAB X with the XC8 compiler under XP and had to re install check to ensure that you don’t have other C compilers in the path this can cause mayhem with pic micro programming and compiling? Or you havent uninstalled the prevous C compiler correctly " easily done as well or remains unoticed "

I have had that problem as well two different versions of a c compiler and low and behold for some reason it mixes up the compilers and you get weird results

Hence why I say if in doubt resort to assembler if this still doesn’t work re install the IDE


See example code as in the datasheet below

[code]
bcf STATUS,RP0 ;Bank 0
clrf GPIO ;Init GPIO
movlw 07h ;Set GP to
movwf CMCON ;digital IO
bsf STATUS,RP0 ;Bank 1
clrf ANSEL ;Digital I/O
movlw 0Ch ;Set GP as inputs
movwf TRISIO ;and set GP
;as outputs
[/code]


Also be aware that every GPIO pin on the PIC12F629/675 has an interrupt-on-change option and every GPIO pin, except GP3, has a weak pull-up option ( Also note this is input only )

This can cause trouble as well if your not used to using this chip so make sure you clear the interrupt on change bit also in the option register make sure this is cleared on init of device

Read the datasheet in full before you start making sure you understand the mapping and bank swapping for different registers

OPTION

Fuses must also be set correctly for this device to work Thats watch dog , brown out detection , internal RC etc Dont get this right nothing else works

What you can do is step through the assembler and debug using MPlabs built in de bugger this assists greatly when checking pin stimulus for example and watching what’s happening to the various registers etc It makes what you are doing allot more understandable You can actually visualize the internals of the IC and work out what’s happening in each register and how you are shifting the data to the ports on output / input

Mark, right now the program I'm trying to create just sets all of the pins (except for GP3) to HIGH in order to light an LED.

Does the debugger run as a simulator or does it actually use the IC via the programmer?

I'll check my path for alternate compilers and verify.

Thanks again for the help. I really appreciate it. This is my first attempt at programming a PIC (or any IC) although I write software for a living so I'm familiar with that aspect of it.

No It runs as a simulator but it will tell you enough to see whats happening

; Specify Device Configuration Bits
;
__CONFIG _
;
org 0x00

Alterantivley you code in c should start like this

[code lang="c"]
ifndef _PIC12F675
#error "This sample code was designed for PIC12F629 next line below is fuse settings "
#pragma DATA_CONFIG, _CPD_OFF & _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_OFF & _MCLRE_OFF & _INTRC_OSC_NOCLKOUT
#endif //_PIC12F675

void main()
{

asm{
bsf _status,RP0
call 0x3ff
movwf _osccal
bcf _status,RP0
}// end asm

// now beging your code for port output

[/code]


See blink below for more notes on this This should help you as well

Also if you want a working program to see how this works or part of your solution then have a look at the coding here this will show you how to set up the registers the fuse settings ports etc

http://www.eeweb.com/project/mark_harrington/single-pic-micro-single-shot-bi-stable-relay

http://www.gooligum.com.au/tutorials/midrange/PIC_Mid_C_5.pdf

To get decent timer values use this see upload for details

Here is the upload for you one packeage does this in assmbler the other does this in proton basic but easily adapated for C

Hi Please find the below code using MPLAB XIDE for LED blinking. It toggle complete GPIOs except GP3 as GP3 is input.


/*
* File: led_blinking.c
* Author: xtechpk
*
* Created on July 12, 2014, 9:49 AM
*/


#include
#include
#include
#include
#include"xc.h"


#pragma config MCLRE=OFF , CP=OFF & CPD=OFF , BOREN=OFF , WDTE=OFF , PWRTE=OFF , FOSC=INTRCIO

#ifndef _XTAL_FREQ
// Unless already defined assume 4MHz system frequency
// This definition is required to calibrate __delay_us() and __delay_ms()
#define _XTAL_FREQ 4000000
#endif


#define BUTTON GP3
#define PERIOD 1000000
#define XTAL 4000000
#define IPERIOD (4 * 1000000 / XTAL) // Period of instruction clock in uSeconds

unsigned char event_state;
volatile bit pb_db_state;
volatile bit pb_change;

/*
*
*/
void sys_init(void);
void delay_cnt(int TIME_Sec);
void delay_cnt(int TIME_Sec)
{
unsigned int cnt_sec = TIME_Sec;
unsigned int cnt_1, cnt_2,cnt_3=0;

for (cnt_sec=TIME_Sec; cnt_sec>0; cnt_sec--)

{
for (cnt_3=7; cnt_3>0; cnt_3--)
{
for (cnt_2=91; cnt_2>0; cnt_2--)
{
for (cnt_1=51; cnt_1>0; cnt_1--)
{
NOP();

}
}
}

}
}





void sys_init(void)
{

GPIE=0;
CMCON =0b00000111;

TRISIO =0;
TRISIO0=0;
TRISIO1=0;
TRISIO2=0;
TRISIO4=0;
TRISIO5=0;
TRISIO3=1;
GPIO =0;
T0IE = 0; // Disable timer interrupt
GIE = 0;
OPTION_REG=0x00;
WPU=0x30;
STATUS=(1

Hi all, I am so sorry for upper code attachment. Very bad way and not understandable.

Please find the attached code here. Thanks