Re: [Uisp-dev] RFC: use uisp as terminal/pty

[Ph. Marek]

On Friday 30 December 2005 16:39, address@hidden wrote:
> I think that some other AVRs may have support for communication over
> this bus with a couple of byte-at-a-time registers, in which case this
> would be a nice idea.  However, I'm just not very familiar with those
> parts.  For example, in the ATMEGA8 the "SPI" port is controlled by the
> registers SPCR, SPSR and SPDR.  This appears to require use of an
> additional pin, SS/ (maybe this pin can simply be tied low?  Doesn't
> seem like much of a 3-wire bus if it requires 4 pins)
You're right, that was my concern too.

> The AVR I'm most familiar with is the at90s2313, an older 20-pin part.
> On it, there's no built-in support for MOSI/MISO/SCK communication---
> instead, it would be necessary to poll SCK and clock the bits in/out of
> the ports manually.  You might be able to do a little better by tying
> SCK and INTx  together, but that's still one interrupt per bit.
I now wrote code for the AVR to do the bit-banging and modified uisp to be 
used as a terminal.

I still see it a big advantage to use the programming cable as communications 
media, and with a few bytes (<30) per second I don't have a problem with the 
interrupts.

I still need to do some clean-ups, but will post my code and diff here, if 
noone objects.


Regards,

Phil