As Kevin Cuzner wrote: > Now, in terms of exactly what gets sent > when, PROGRAMMER->cmd is the important one...avrdude will give the > commands to the programmer 4 bytes at a time along with a buffer to fill > with whatever was received through that function.
The main reason for this is that AVRDUDE started out as a programming tool for simple parallel-port bitbang adapters. Thus, ISP has to be implemented completely inside AVRDUDE, and this approach has been kept for as long as possible. For that reason, even the STK500 (and STK500v2) implementation still all do the ISP manually, using the "generic SPI" command there as much as possible. That's basically what the programmer's cmd method is for. If you've got a more sophisticated programmer, you can alternatively implement read/write functions for byte and page access yourself, and leave the "cmd" method out. For an example for this, have a look at the JTAGICE (mkII and 3) implementations. As they don't use ISP at all, there had to be methods now that leave all the lowlevel work to the programming hardware. Feel free to write up all your findings into some kind of document that can go into the AVRDUDE tree if you want. -- cheers, Joerg .-.-. --... ...-- -.. . DL8DTL http://www.sax.de/~joerg/ Never trust an operating system you don't have sources for. ;-) _______________________________________________ avrdude-dev mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/avrdude-dev
