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pic16f767 #fuse problem

 
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Nick
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pic16f767 #fuse problem
PostPosted: Wed Sep 22, 2004 11:40 am     Reply with quote
I have tested this main() code a 16f876 and it worked.

It seems that the clock is off, seems like its not using the external clock. Is something wrong with the #fuses? I am trying to use a 1mhz external clock.

Thanks

Nick




Code:
#include <16F767.h>
#fuses LP,NOWDT,NOPROTECT,EC_IO

#use delay(clock=   1000000)
#use rs232(baud=1200, xmit=PIN_C6, rcv=PIN_C7)  // Jumpers: 8 to 11, 7 to 12



void main() {           // This function waits for either ~2ms or until a


  while(true)
  {
    output_high(PIN_B3);
    delay_us(1000);
    output_low(PIN_B3);
    delay_us(1000);
    printf("Hello\n");
  }


}
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Wed Sep 22, 2004 12:32 pm     Reply with quote
Quote:
#fuses LP,NOWDT,NOPROTECT,EC_IO

You have two oscillator settings in your #fuses statement.

You've got LP ("Low power oscillator") which is for a 32 KHz
crystal and you've got EC_IO ("External clock with RA6
configured as an I/O pin").

You need to get rid of one of them.
Nick
Guest
PostPosted: Thu Sep 23, 2004 1:01 pm     Reply with quote
I removed the internal fuse and It still wants to use the internal 32khz clock.


Anyone have any ideas? I have the physical setup correct because I have test it with an 876 chip and it works perfect.

Nick



Code:
#include <16F767.h>
#fuses NOWDT,NOPROTECT,EC_IO

//#use delay(clock=      32000)32khz (internal
#use delay(clock=   1000000) //1mhz
#use rs232(baud=110, xmit=PIN_C6, rcv=PIN_C7)  // Jumpers: 8 to 11, 7 to 12



void main() {           // This function waits for either ~2ms or until a


  while(true)
  {
    output_high(PIN_B3);
    delay_us(1000);
    output_low(PIN_B3);
    delay_us(1000);
    printf("Hello\n");
  }


}
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Thu Sep 23, 2004 1:14 pm     Reply with quote
What's your version of the compiler ?
Nick
Guest
PostPosted: Thu Sep 23, 2004 1:20 pm     Reply with quote
pcm 3.187 purchased a licence about 20 days ago.

Nick
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Thu Sep 23, 2004 1:57 pm     Reply with quote
You might try adding the line shown below in bold. According to
the data sheet, the PIC is supposed to power-up in "OSC_NORMAL"
mode by default, but try it anyway.
Also, what pin on the PIC are you applying the 1 MHz clock to ?
What is generating the 1 MHz clock ?

#include <16F767.h>
#fuses NOWDT,NOPROTECT,EC_IO
#use delay(clock=1000000)
#use rs232(baud=110, xmit=PIN_C6, rcv=PIN_C7)
void main()
{
setup_oscillator(OSC_NORMAL);
while(true)
{
output_high(PIN_B3);
delay_us(1000);
output_low(PIN_B3);
delay_us(1000);
printf("Hello\n");
}


}
Nick
Guest
PostPosted: Thu Sep 23, 2004 2:12 pm     Reply with quote
I have a CR 1mhz clock. I got it from digi key, someone from this board recommended it. It has work great with the 876 chip.

I added that line and it didnt fix the problem.

I guess I should report this as a bug.


Nick
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Thu Sep 23, 2004 2:18 pm     Reply with quote
I don't know if it's a bug. It just means that you or I don't
completely understand the problem, as of this point.
The 16F767 has a more complicated selection of oscillator
modes than the 16F876. I don't have one to test, and I
don't know your test circuit for sure.

By the way, what is "CR" ? What does it stand for ?
What is the Digikey part number ?
Nick
Guest
PostPosted: Thu Sep 23, 2004 2:24 pm     Reply with quote
My test board is working, atleast with the 876. It will work if I change the clock to 37khz in the 767 code. So I'm pretty sure that the test board is working. Its just an LED + resistor and a max 232 hooked up and given 3v. Nothing fancy. I am trying to get this setup working first before I try it on the actually project board.

CR = Ceramic Resonators

My 1mhz clock is from Digikey pn# X926-ND. www.digikey.com pg. 626


Thanks for the help,

Nick
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Thu Sep 23, 2004 2:43 pm     Reply with quote
OK. Finally, we're getting somewhere.

A ceramic resonator is not an "external clock".
Furthermore, the one that you are using is not a 3-pin type,
so it's going to need external capacitors in order to work properly.
See the data sheet here:
http://www.ecsxtal.com/pdf/ztb.pdf
According to the 16F767 data sheet, you should use "XT" mode
for a 1 MHz resonator. So change your #fuses statement to be:
#fuses XT, NOWDT,NOPROTECT

When you said "external oscillator", you used a term that refers
to this type of device: http://www.ecsxtal.com/surfosc.htm
These are complete oscillators in a "can" package. (but can also
be in plastic packages).
Nick
Guest
PostPosted: Fri Sep 24, 2004 9:45 am     Reply with quote
I swapped out the 2 pin clock for a 3 pin type clock and a square metal clocks, both work with the 876, but the 767 is still using the internal clock.

I was looking at the function you posted

"setup_oscillator"

There should be a 1mhz internal clock in the chip that I can use. I would like to figure out out the function "setup_oscillator" works but its not in my help file.

Nick
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Fri Sep 24, 2004 12:11 pm     Reply with quote
Quote:

I would like to figure out the function "setup_oscillator" works but it's not
in my help file.

For information on that function, look in the README.TXT file in this
folder: c:\Program Files\Picc

For a list of parameters used with that function, look in the 16F767.H
file. It's in this folder: c:\Program Files\Picc\Devices
Guest
PostPosted: Fri Sep 24, 2004 12:57 pm     Reply with quote
PCM programmer wrote:
Quote:

I would like to figure out the function "setup_oscillator" works but it's not
in my help file.

For information on that function, look in the README.TXT file in this
folder: c:\Program Files\Picc

For a list of parameters used with that function, look in the 16F767.H
file. It's in this folder: c:\Program Files\Picc\Devices



Thanks, I got it


Here is the corrected code

Code:


#include <16F767.h>
#fuses NOWDT,NOPROTECT
#use delay(clock=1000000)
#use rs232(baud=4800, xmit=PIN_C6, rcv=PIN_C7)
void main()
{
setup_oscillator(OSC_1MHZ);
while(true)
{
output_high(PIN_B3);
delay_us(1000);
output_low(PIN_B3);
delay_us(1000);
printf("Hello\n");
}


}

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