Patchouli

Hi.

If it were your project, what would you implement for field programming by users of an '877 based circuit? A complete bootloader, just basic downloader code, or a cheap, low parts count on-board programmer circuit like a JDM or Tait? ... other options?

I'm leaning toward bootloader. A few hundred words in an 877? Who cares? But an on-board programmer would be good; no matter what happens to the code you can always flash it. (like the bootloader writes over itself or something weird.)

But again:

<--- clueless

Thanks.

motion

I would recommend adding a bootloader as well as ICSP/ICD capability in your projects. This aids in debugging since you don't have to remove the chip from its socket to reprogram.

You can fit a bootloader within the last 256 locations in the program memory and write protect that area.

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Zacman

I guess I'm not totally clear on how the ICSP works. I have read some things that say parts could be damaged by the higher voltage from the serial port.

I tried it out the other day and couldn't get it to work on an 876a. I connected the various wires as they should but the one thing I wasn't clear about was if I was suppose to attach a resistor from mclr to ground or to vdd. I was using the pg2 programmer and it wasn't working.

Anyone have any good sites on ICSP.

motion

You can start with Microchip's site on the ICD2.

http://www.microchip.com/1010/pline/...icd2/index.htm

You can also google using the keywords "Microchip ICD2".

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"Having to do with Motion Control"