From: eLinux.org
Here are some debug assist boards that you might find useful.
- Olimex JTAG USB OCD device - see
https://www.sparkfun.com/products/7834
- has USB JTAG, RS232 (full modem signals supported) port; and power supply all in one compact device
- Abatron BDI3000 - see http://www.abatron.ch/products/bdi-family/bdi3000.html
- Sony Debug Assist
board (also
known as CDB Assist)
- provides power supply, USB pass-through to host, and control of 3 "buttons" via USB connection on host
- Target Switch Control From Parallel
Port
- an old design for controlling switches using a computer's parallel port lines
- BayLibre ACME cape (for BeagleBone Black) - see
http://baylibre.com/acme/
- supports different power measurement probes via a standard connector
- presentation on issues at: http://events.linuxfoundation.org/sites/events/files/slides/Leveraging_Open-Source_Power_Measurement_Standard_Solution_0.pdf