| ??? 03/20/07 04:15 Read: times |
#135344 - True, but you can get around this... Responding to: ???'s previous message |
Andrew Ayre said:
A plain 80C51 doesn't support ISP.
...for example parallel programming. As Andy pointed out, the 8051 doesn't necessarily have to support ISP to use the concept of ISP. Using a parallel interface, and some on-board glue logic, I believe you can use a flash memory chip or EEPROM for code space, hold the processor in RESET state (which forces the ports to inputs - sorry, "quasi-bidirectional" non-outputs), Jan Waclawek said:
and upload your code to the pogram chip. When you release the RESET, have your glue logic tri-state the parallel interface, and the processor will begin running the code in the code memory. It's a little crude, and doesn't provide for in-circuit debugging, but can be accomplished. Unfortunately, I don't believe you can brute force your own IAP, since it requires using the 8052, which needs to be held in RESET state while writing to FLASH... Please note, I have not done this myself...I have only read about it while searching for the perfect ISP system to build. I ended up going with the uPSD3334 processor from ST Micro... -db |
