RE: [avrdude-dev] Re: STK500v2 Programmers (was Hello)

[Wouter van Gulik]

> Matthias Weißer wrote a bootloader that supports a minimal STK500
> protocol, and fits into the boot section of an ATmega8.  I'm not quite
> sure, but I think a reasonable subset of STK500v2 might be even
> smaller, as it basically doesn't need device tables anymore.  All the
> per-device parameters are passed down as part of each respective
> command.
> 

There is however one catch. The current stk500v2 implementation in avrdude
(for ISP) is via the CMD_SPI_MULTI. It a sort of raw SPI stream (I guess,
never really looked into it). This raw mode should easily fit in a 2K
device. The raw mode is not supported by AvrStudio.
The same problem arises for a bootloader that supports stk500v2, it depends
on what you want to support, avrdude or AvrStudio.

Are there any plans on supporting programming ISP via the opcodes? I know
the HVSP/Parallel is done via the commands and ISP is just a copy of that
using different opcodes.

I did a AvrStudio compatible stk500v2 bootloader that fits in 512 bytes. It
does not support eeprom and lockbits programming. But the rest (reading
flash/lockbits/fuses/signature and writing flash) is supported.
I must admit it is a tough job but it can be done. It is also easy to
emulate a HVSP/Parallel programming, you only need to change the command
code set.

HTH,

Wouter