SPI SLave

Hey all,

There is an easy spi master port in avrco, but is there also a simple spi slave driver in avrco for the xmega?
Someting similar like there is for the serport :
- an import were to configure the spi port (Slave, mode0..4, bit order)
- a tx buffer you can put data that is shift out if the spi master delivers the clock (interrupt based?)
- a rx buffer that is holding the bytes that were shifted in by the spi master (interrupt based?)

The setup I have is as follows:
An xmega with a spi master port that is connected to a LCD display with spi bus. On that same bus I need to connect a second xmega (working as slave). The load of the slave xmega is high but the communication between master and slave is minor.
(Taking other ports on the xmega is not an option)

Thanks for some help

Peter

FWIW

I have created SPI slaves using MEGA (not XMEGA chips), and they worked very well, but Rolf is right in his concerns. The temptation is to run SPI as fast as possible, but if you are using MEGAs as slaves you actually need to run SPI as slowly as possible to get reliable operation - it should still be plenty fast enough. In fact I deliberately ran the master with a slow crystal just to make sure. This is not the way the AVRCo SPI master is implemented, and if I were doing it again I would, as Rolf suggests, use the UARTS.

In summary - been there, done that, wouldn't do it again.

Hi Peter.

Another option might be the SC16IS750 chip, which converts I2C to UART. That might avoid the extra complications.