compiling usbtinyisp firmware

USB AVR Programmer and SPI interface. Adafruit's USBtinyISP.

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westfw
 
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compiling usbtinyisp firmware

Post by westfw »

Is the only reason that the usbtinyisp firmware can't be compiled with a current version of gcc that the code comes out too big? I was looking at the "64k" limitation, but having to install an old and obsolete version of avr-gcc (ANOTHER one, I mean!) is obnoxious.

If so, can you just throw in an ATtiny4313 and get "plenty" of memory?

Also, I manged to get the executable down to 2006 bytes (w gcc 4.3.2) by changing an (unnecessary) int to byte_t, and using some bootloader tricks (shortening the vector table to include only the vectors needed.) There's more space to be saved by eliminating zeroing of bss and using custom .data initialization (1980 bytes.)

I don't know whether it works, though.

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westfw
 
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Re: compiling usbtinyisp firmware

Post by westfw »

Actually, I notice that the usbtiny original creator (Dick Streefland) has a version of usbtinyisp firmware that is several versions newer than the version downloadable from Adafruit (which seems to have "fixed" the avr-gcc version/size problems in other ways.) Is there a reason it's not being used?

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