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yann
Joined: 06 Dec 2004 Posts: 3
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ICSP maximum baudrate? |
Posted: Thu Dec 30, 2004 8:02 am |
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Hi to everyone,
Can anybody help me? I woulf like to know the maximum baudrate for programming a PIC (16f877) by ICSP? I would reprogram the PIC through a DSP allowing a 1Mbps baudrate.
Thanks,
Yann |
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PCM programmer
Joined: 06 Sep 2003 Posts: 21708
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Posted: Thu Dec 30, 2004 2:31 pm |
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Go here:
http://www.microchip.com/stellent/idcplgidcplg?IdcService=SS_GET_PAGE&nodeId=1335&dDocName=en010241
Download this document:
PIC16F87X EEPROM Memory Programming Specification
Look at the chart on page 18. They give the minimum setup and
hold times before and after the falling edge of clock. Since that's
100 ns each, that means the total is 200 ns, so data can change
every 200 ns. That means the clock can run at 5 MHz, maximum.
Of course, the data takes time to transition from one level to another
so the maximum clock speed is really somewhat less than 5 MHz.
There are also other delays that must be inserted inbetween groups
of bits. See the timing diagrams in the docment above.
To be safe, I wouldn't run the clock anywhere near the maximum
speed. I would probably run it at 1 MHz, max. But that's just me. |
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yann
Joined: 06 Dec 2004 Posts: 3
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Posted: Mon Jan 03, 2005 2:45 am |
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thank you for your help.
Yann |
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