Robotics | Main / GumstixVerdex

Gumstix on Flickr

The main computer on the robot is a Gumstix Verdex XM4-bt . It was chosen for its extremely small form factor, features, ease of use, and expandability. It has a 400 Mhz PXA270 ARM processor from Marvell, 64 MB of RAM, and 16MB of on-board flash memory for OS and program storage.

Initial connection to the Verdex was made through the FFUART using a USB-Serial adapter.

Before you can compile any code for the Verdex, you have to create a cross-compiling toolchain and flash the filesystem ? onto the board.

Bluetooth

When we got the motherboard, the factory flash image (r1161 at the time I believe) supported the bluetooth on the gumstix. It was fairly straightforward to follow some directions to connect to the computer wirelessly over bluetooth.

Upon flashing the filesystem, however, bluetooth stopped working completely. There is the all-too common startup messages of:

Starting Bluetooth subsystem: 
Trying baud rate 921600... 
No response after reset 
No response from BT module 
Trying baud rate 921600... 
No response after reset 
No response from BT module 
Trying baud rate 115200... 
No response after reset 
No response from BT module 
Trying baud rate 57600... 
No response after reset 
No response from BT module 
Can't initialize device: Success

We wrote it off as broken/not worth the effort to fix. There have been many threads on the gumstix mailing list about possible fixes, patches, etc... with many successes and just as many failures. After choosing our Buildroot revision to work with and still no bluetooth support, we figured all was lost. Until we installed the curses library. Upon flashing ? the filesystem again, bluetooth magically started working again. My advice: keep trying if you absolutely need it to work, otherwise, just use wifi for wireless access.