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victor_constantin
Joined: 14 Dec 2010
Posts: 10
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| Issue with internal oscillator on PIC12F675 |
 Posted: Wed Dec 15, 2010 3:41 am |
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Hello guys,
I'm trying to create a blink led program for a 12f675 using CCS. Problem is i can only get the led's to register to the first state in the program, thus, no blinking, just on/off depending on the first state of the pin declared in the main loop.
I tested this with a blinkled program in MPLAB and it works fine so the issue is with CCS, not the PIC. The code is below. Any ideas would be much apreciated.
| Code: | #include "D:\Pic\test2.h"
void main()
{
port_a_pullups(TRUE);
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_CLOCK_DIV_2);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_1(T1_DISABLED);
setup_comparator(NC_NC);
setup_vref(FALSE);
#use delay(clock=20000000)
int foo;
foo=1;
while (foo==1)
{
output_high(PIN_A5);
output_low(PIN_A4);
output_high(PIN_A3);
output_low(PIN_A2);
output_high(PIN_A1);
output_low(PIN_A0);
delay_ms(500);
output_low(PIN_A5);
output_high(PIN_A4);
output_low(PIN_A3);
output_high(PIN_A2);
output_low(PIN_A1);
output_high(PIN_A0);
delay_ms(500);
}
} |
Below is the header file
| Code: |
#include <12F675.h>
#device adc=8
#FUSES NOWDT //No Watch Dog Timer
#FUSES INTRC_IO //Internal RC Osc, no CLKOUT
#FUSES NOCPD //No EE protection
#FUSES NOPROTECT //Code not protected from reading
#FUSES MCLR //Master Clear pin enabled
#FUSES NOPUT //No Power Up Timer
#FUSES NOBROWNOUT //No brownout reset
#FUSES BANDGAP_HIGH
#FUSES RESERVED //Used to set the reserved FUSE bits
#use delay(clock=20000000) |
I couldn't really find anything to solve this on the forum, please point me in the right direction if there is a thread i missed that could help. |
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Wayne_
Joined: 10 Oct 2007
Posts: 681
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| Posted: Wed Dec 15, 2010 5:30 am |
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I expect your 500ms delay is more like 500 seconds! (exageration)
You are using INTRC (internal rc clock) and you have #use delay(clock=20000000)
I doubt very much the internal clock on that pic can run at 20MHz!
I am having trouble accessing the datasheet at the moment so someone else will have to confirm this. |
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victor_constantin
Joined: 14 Dec 2010
Posts: 10
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| Posted: Wed Dec 15, 2010 5:38 am |
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| Yes, you are right, it's a 4Mhz oscillator. However, i now changed that setting to #use delay(clock=4M) but to no avail. |
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Geps
Joined: 05 Jul 2010
Posts: 129
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| Posted: Wed Dec 15, 2010 6:41 am |
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| Code: | int foo;
foo=1;
while (foo==1)
{ |
What's the purpose of this? It looks messy and overcomplicates the program.
Try changing to |
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Geps
Joined: 05 Jul 2010
Posts: 129
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| Posted: Wed Dec 15, 2010 6:42 am |
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Another point, you don't need
| Quote: | | #use delay(clock=20000000) |
in both header and source file - unless using two sets of delays. Since you're not, just delete one. |
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victor_constantin
Joined: 14 Dec 2010
Posts: 10
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| Posted: Wed Dec 15, 2010 5:09 pm |
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Sorry for the late reply and thanks for the answers. However, i wasn't able to solve the issue, the program still runs in the same way. Any other ideas?
From what i've gathered so far, the problem is with the internal clock, the PIC seems to get hung as soon as it hits the delay instruction. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Dec 15, 2010 5:20 pm |
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1. What is your CCS compiler version ? It's a 4-digit number (only)
and is given at the top of your .LST file, which will be in your project
directory after a succesful compilation of your project.
2. Do you have a pull-up resistor on the MCLR pin of the PIC ?
What is the value of the resistor ?
3. What is the Vdd voltage of the PIC ?
4. Do you have a series resistor in your LED circuit ?
Example:
| Code: |
pin 330 ohms LED
GP2 ----/\/\/\/------->|----
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----- Ground
---
-
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My advice is, don't try to to light up 5 LEDs. Disconnect all, except one. |
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victor_constantin
Joined: 14 Dec 2010
Posts: 10
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| Posted: Wed Dec 15, 2010 5:27 pm |
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Hello,
1. Version is 4.104
2. No resistor in series with the MCRL pin. What would be the correct value? What would be the correct way to wire it?
3. Vdd voltage is 5.5V
4. Yes, there is a resistor. As i've stated in the first post, the circuit is functional, tested with another program in MPLAB. Only two LED"s connected at the current time but it works with all connected. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Dec 15, 2010 5:39 pm |
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If you're using the NOMCLR fuse, you don't need the MCLR resistor.
What pins do you have LEDs attached to on the PIC ? What pin numbers ?
Why is your Vdd set at +5.5v ? Why not use the usual voltage of +5.0v ? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Dec 15, 2010 6:20 pm |
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I don't have time to wait for your reponse on the LED pins.
I just want to get this done.
I installed vs. 4.104 of the compiler. I used a Pickit2 Low Pin Count
board for this test. I removed the 16F690 from the board's socket and
installed a 12F675 in the upper portion of the socket. I added a jumper
wire from pin RA2 on the board (GP2) to an LED on the board.
I then compiled and loaded this program with the Pickit2. It works.
It blinks the LED:
| Code: |
#include <12F675.h>
#fuses INTRC_IO, NOWDT, PUT, BROWNOUT, NOMCLR
#use delay(clock=4000000)
#define GP0 PIN_A0
#define GP1 PIN_A1
#define GP2 PIN_A2
#define GP3 PIN_A3
#define GP4 PIN_A4
#define GP5 PIN_A5
//==============================
void main(void)
{
while(1)
{
output_high(GP2); // Blink LED on pin GP2
delay_ms(500);
output_low(GP2);
delay_ms(500);
}
} |
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victor_constantin
Joined: 14 Dec 2010
Posts: 10
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| Posted: Thu Dec 16, 2010 3:18 am |
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| Hello, sorry for the late response. I managed to fix it after all, the problem was indeed with the NOMCLR. Thanks alot guys. |
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