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jseidmann
Joined: 04 Nov 2004
Posts: 67
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 Posted: Fri Mar 24, 2006 12:51 pm |
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PCM,
We manufacture a finished product here and there is a socket where the microcontroller goes. I have simply switched the PIC18F252 to the PIC18F2620 and burned the HEX file to it. The circuit allows being programmed in circuit. I am using an oscilloscope to view the signal off of pin C1. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Mar 24, 2006 1:48 pm |
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Look at this errata document for the 18F2620:
http://ww1.microchip.com/downloads/en/devicedoc/80224b.pdf
It says:
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8. Module: ECCP and CCP
The CCP1 and CCP2 configured for PWM mode,
with 1:1 Timer2 prescaler and duty cycle set to the
period minus 1, may result in the PWM output(s)
remaining at a logic low level.
Clearing the PR2 register to select the fastest
period may also result in the output(s) remaining at
a logic low output level. |
This doesn't fit your exact situation but partly it does.
You may be experiencing a related problem. Microchip may not know
all of the erratas that exist in that PIC. You may have found another
one.
I would take a small test program and start to change the parameters
slightly. Use a different timer prescaler. Try to find a point at which
it starts working.
If nothing works, and there's no work-around, then select another PIC
that doesn't have that errata. |
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jseidmann
Joined: 04 Nov 2004
Posts: 67
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| Posted: Fri Mar 24, 2006 3:23 pm |
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PCM,
Thanks for your post! I tried it with a T1_DIV_2 and that worked no problem. I just had to change the CCP_1 value to get the frequency to what it should be and voila, it worked perfectly. Thank you for all your help, I certainly couldnt have gotten this fixed without you all. |
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