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Pic micro External memory

juantravel

May 14, 2010
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I have been playing with pic micros for quite some time now. I was thinking of writing a small OS. Im thinking of storing the OS kernal on a sd card and loading it to memory. How would i go bout loading it into memory?

I googled a bit before work and found an article that some pic micro's support processor mode which allows external programming memory. That requires 19 pins tho... Is there a way to implement this function in software, sort of like the sram from pic micro.
Thank you
 
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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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And here it is that you discover a problem with Harvard architecture as opposed to von Neumann architecture.

You should look at some of the various boot loaders available. It may be possible to load the code into the main program memory using fewer control lines by loading it from a serial eeprom. I'm not sure that there are any that are set up to dynamically load code using any of the serial bus interfaces, so you may have to roll your own.

This method will be slower, and will use up rewrite cycles of your program memory too.

I also can't vouch that it would work, however I can't see any particular reason why it would not.
 
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