Can a low-end ARM (Coretex M0+) run enough of a stack to use a USB wifi dongle?

Question

I currently use full-blown wifi modules (like Roaving networks RN-174 or the LS research TiWi module (http://www.lsr.com/wireless-products/tiwi-sl)) to interface with lower powered microcontrollers.

However, the low-end ARMs (like the Cortex M0+) are getting very power efficient, and a benefit would be if I could use more commercial wifi dongles (like http://www.trendnet.com/products/proddetail.asp?prod=195_TEW-648UBM ) and possibly benefit from additional power savings (the wifi modules I use typically have an ARM processor to run the stack and other parts of the protocol).

Typically, these require a processor running LINUX with a full driver implementation; I was wondering if any driver/stacks existed for the lower-end ARMs to drive a usb wifi dongle?

Thanks!

Answer 1

I'm not aware of any M0 or M0+ chips with USB host, but it is available on some M3s, for example NXP's LPC17xx series. An LPC1768 is used in the mbed module , and there are a few USB host implementations available for it, including a library for a 3G (not WiFi) Vodafone dongle . There is also a generic USB library for NXP chips - nxpUSBlib .

Depending on the dongle, sometimes it might offer not only USB interface, but also plain UART. In a few cases it's possible to access UART serial interface after minor modification of the dongle. If you have such an interface, you don't need USB at all, and UART is available on pretty much any ARM, no matter how low-end.

Please note that getting the USB or UART connection is only half of the job - you still need to discover how to configure and connect your specific dongle. If it uses a standard protocol like USB CDC/ACM and AT commands, that's good, but it's not guaranteed. Sometimes you'll have to reverse engineer proprietary drivers to discover the magic values. Some modules require the firmware to be sent to them on boot, so you'll have to store the firmware image somewhere. Though if it has a Linux driver, there's a pretty good chance it can be made to work.