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i2c_start() fail

 
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pyu



Joined: 04 Feb 2009
Posts: 51

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i2c_start() fail
PostPosted: Wed Apr 24, 2013 2:14 am     Reply with quote

Hello.

I have a pickit2 with 16f887 and ds1307.
I used this hardware last time in 2009.
Now, isn't working any more.

Code:
void ds1307_init(void)
{
   BYTE seconds = 0;

   i2c_start();

...

}


Somehow, it creating a infinite loop here (I made a debug), it's never pass from this line:
Code:
i2c_start();


What can be the problem for this? Any ideas?

Thanks.
temtronic



Joined: 01 Jul 2010
Posts: 9243
Location: Greensville,Ontario

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PostPosted: Wed Apr 24, 2013 5:27 am     Reply with quote

some ideas...
...assuming the PIC will run a '1Hz blinking LED program

1) no battery on the 1307 ?

2) no I2C bus pullups ?

3) download PCM programmer's I2C 'scanner test program' and see what happens.

If code was working, logic says it's a hardware problem..

hth
jay
pyu



Joined: 04 Feb 2009
Posts: 51

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PostPosted: Wed Apr 24, 2013 6:00 am     Reply with quote

temtronic wrote:
some ideas...
...assuming the pIC will run a '1Hz blinking LED program

1) no battery on the 1307 ?

2) no I2C bus pullups ?

3) download PCM programmer's I2C 'scanner test program' and see what happens.

If code was working, logic says it's a hardware problem..

hth
jay


Thanks for your fast response.

1 - maybe battery is dead. will try another battery. current one is there since 2009, when I worked last time with my pickit2.
2 - I have those 2 resistors. it worked last time in 2009.
3 - where can I find this scanner test program?

Thanks!
Mike Walne



Joined: 19 Feb 2004
Posts: 1785
Location: Boston Spa UK

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PostPosted: Wed Apr 24, 2013 6:13 am     Reply with quote

Quote:
3 - where can I find this scanner test program?

Do a search on this forum

Search for keyword "i2c"
Search for author "PCM programmer"
Set search for ALL terms

Mike
pyu



Joined: 04 Feb 2009
Posts: 51

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PostPosted: Wed Apr 24, 2013 6:55 am     Reply with quote

I think this is it:

http://www.ccsinfo.com/forum/viewtopic.php?t=49713&highlight=i2c

Thanks, I will give it a try Smile
pyu



Joined: 04 Feb 2009
Posts: 51

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PostPosted: Wed Apr 24, 2013 1:06 pm     Reply with quote

I made a test, it crashes on this line:
Code:
status = i2c_write(address);  // Status = 0 if got an ACK


I replace the battery, same problem :(
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Wed Apr 24, 2013 2:28 pm     Reply with quote

Look at the SCL clock line with an oscilloscope. Is it stuck at a low level ?
If so, verify that the pull-up resistor is really connected. Make sure
the ds1307 has power. Remove the ds1307 from the circuit to see
if the test program still locks up.
pyu



Joined: 04 Feb 2009
Posts: 51

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PostPosted: Thu Apr 25, 2013 2:24 am     Reply with quote

Hi.

I re-soldered all the wires and resistors, and now it's working Smile

Thanks.
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