Since it looks like the new USB XMega's are just about mission ready, we are looking for examples of USB-SPI and sustainable speed numbers ?
The task is broadly similar to a large device programmer, but with more balanced Tx/Rx loads.
We need > ~2MBd, each way, which pushes UART solutions,
Xmega looks like a good fit, if we can find the SW side. Price seems to have come down, and bugs seem to be fixed since I last looked.
Other candidates are
* FT232H : should meet speed, but moderately expensive.
* FT-X series - less sure about speed, but better price and very small packages, but we still need a uC
* PSoC3 : expensive, no small packages.
* VNC2 : Moderate price, good code size, has small packages, but lacks ADC.
* PIC18 : Versions with enough RAM climb in price
* PIC32 : Might also fit, does have good RAM.Code choices, in smaller packages, but this app does not really need a 32 bit CPU.
I've seen comments suggesting LUFA is almost XMega ready - but the website seems further back than posts here suggest ?
What other USB-SPI Xmega SW alternatives are there, and what Xmega HW PCB platforms are a good development base for USB-SPI work on the XMega ?