Hello everybody!

This discussion is part of an exploratory, feasibility study. I would like to use this radio: http://dl.ubnt.com/xr9_datasheet.pdf to bridge two mbeds that are two miles apart.

The biggest challenge is the PCI bus IO that the radio has. Anybody ever built a PCI driver here? I'm only asking because there seems to be nothing on the subject (of PCI) after searching here. Anyone have an experienced opinion as to the feasibility of interfacing this radio with the mbed?

I value any insight or advice offered.

The mbed is probably a poor choice for driving such a high speed parallel bus - not that you can't do it but it would be better to use a microcontroller with more digital output pins and possibly a dedicated interface chip.

If you just need a high bandwidth data bridge over two miles you might try the Ubiquiti Bullet (unfortunately, no 900MHz band available) and interface to the mbed's ethernet PHY. The LPC1768 ethernet DMA is one of the fastest peripherals on the mbed, although performance is often crippled by slow generic protocol handlers (TCP/IP, etc). UDP is a nice compromise - a readily interoperable protocol with low overhead. Especially for packetized data (telemetry, data chunks) UDP is the way to go.

If you don't really need WiFi bandwidth, use a serial radio modem (i.e., Digi /Freescale / Microhard) - it should be easy to get at least 115200 baud at 2 miles with omni antennas.These should plug and play on any mbed UART, although you might need to implement some flow control to keep from flooding the link, especially over zigbee modems.

HTH, Matt