[avrdude-dev] avrdude and FT2232

[Ville Voipio]

Hello all,

I have a bunch of programmable chips which need to be programmed in 
production. There are a couple of AVR's (mega8) and then a bunch of 
other processors (ARM) and logic (Xilinx, Altera, Lattice) which need to 
be programmed. AVR's use SPI, others JTAG.

As the SPI interface and the JTAG use the same number and type of lines, 
they can be handled with a single programmer, as far as the pin numbers 
are correct.

I have been able to accomplish this with a custom-made parallel port 
programmer and slight tweaking of avrdude (plus some other open source 
programming software). However, parallel port is no more, and I need to 
move into USB.

The problem here is that direct bit-banging on USB is very slow. On the 
other hand, numerous USB dongles (such as Olimex USB-JTAG, Amontec) 
utilize the same chip, FT2232. This chip has the MPSSE engine which 
talks both SPI and JTAG rather fast when configured correctly.

Now my intention is to implement this functionality into avrdude (= 
support for FTDI2232-based MPSSE). However, before doing anything, I 
would like to know I am doing the right thing.

- where should I start? I have the source of avrdude 5.5, and I have a 
general idea of what happens in it. Should I get the newest source from 
the CVS, or is it better to stick to the released one?

- libftdi and d2xx seem to require slightly different handling. Is it 
necessary/desirable to make both? (I am slightly inclined towards D2XX, 
but I do understand the open source point very well.)

- has someone done something to this direction already?

- anything elsi I should be aware of?

Thanks for any input!

- Ville