Clearing Eeprom on protoboard?

Carl Lawhon

Here's my problem:

Earlier today I loaded a large program to the 64kb eeprom memory on my protoboard. Right now I am trying to load a significantly smaller program to the eeprom. Whenever I load the program, however, random bits of the first program run while the new program is running. Alternatively, sometimes the new program runs improperly. Can clearing the eeprom solve this problem? If so, how should I go about doing that?

mctrivia

the loader should clear the first 32KB EEPROM. Anything after that is not used generally by the propeller.

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Mike Green

There is no need to clear the EEPROM. I don't know why you're seeing "odd behavior", but it's not that there's random bits of an "old program" running. When the Propeller Tool downloads a program to the Propeller, it initially gets downloaded to RAM and all RAM beyond the end of the program gets zeroed. When the program is written to EEPROM, the entire 32K of RAM is written to 1st 32K of the EEPROM, so anything previously in the 1st 32K of EEPROM is overwritten. The 2nd 32K is another story. It's not touched at all by the bootloader. Anything written there by your program will remain there until changed. You cannot download a program larger than 32K using the bootloader (and the Propeller Tool). If you program is very large (close to 32K in size), it may be running out of stack space. This extends from the end of the program to the end of RAM.