First, thanks to all contributors for a brilliant forum. I've found answers to questions here many times over the years.
I'm working on some hardware and software for building control / home automation. The hardware is mainly based on Xmega MCUs, so far I've used the 64D4, the 64A4 and am about to use a 32E5. The core of the work is an RS485 bus for comms between sensors/actuators and a "bridge" to a wired ethernet LAN. It makes it simple to create a sensor/actuator device which communicates with a LAN connected controller; the device hardware and software needs only to deal with the (simple) RS485 side of things, and can therefore be designed quickly and easily. As an aside, I do the bridging with a Wiznet Wiz850io module (based on their W5500 SPI-ethernet chip); getting this working was an interesting journey of discovery with both standard and USART SPI controllers, and also the DMA controllers in the Xmega A (the USART does SPI mastering faster, and the DMA controllers didn't help).
So... I have found myself wishing there was an Xmega counterpart of the Arduino Mega - or something like it - for rapid prototyping. My question is: how useful would a Raspberry Pi form factor dev board with an Xmega be to you all? The Pi ecosystem is 3.3V friendly so it seems a better fit than the Arduino.
I'm thinking of designing 2 versions:
1) Pi model B+ format
- (say) Xmega 128A3U MCU
- Pi compatible 3.3V GPIO header, with auxilliary header for ADC/DAC signals
- Wiznet W5500 SPI-ethernet chip with RJ45 magjack for LAN connectivity
- micro USB for power in during development, with data lines connected to USB signals for 'U' variants of the Xmega
- optional DC-DC converter for 7-24V DC in
- optional xtal
- optional RTC
2) Pi model A format
- as above, but physically smaller and without ethernet
The "PiLoT" name means "Pi form factor, LAN of Things"...
Grateful for any thoughts and suggestions. If I do design these things, I'll publish the result under some sort of free/open licence.