I was wondering wheter it is possible to program the Atmega chip over the Pi's uart.
The way i understand it, the atmega chip supports programming trough its serial port.
However, this is mostly done by using some usb to serial cable.
The question arises because i need to use the atmega's SPI port, and i'm not willing to sacrifice a usb port either.
Thanks in advance,
Yes you can - however - you first need to get the bootloader into the ATmega on the Gertboard - but that can be a one-off operation. The next issue is that the bootloader needs to know that the ATmega is running at 12MHz, else the baud rate will be wrong. Finally, there is the issue of auto-resetting the ATmega prior to loading new code into it - this can be solved by using a single GPIO line from the Pi.
I've had some personal (family) issues the past few weeks which is getting in the way, but it's on my to-do list along with a lot of other new stuff for the Gertboard too - hang in there, or use the above as a starting point