Robostix power

This page uses the term robostix interchangably with the roboaudiostix, unless explicitly mentioned otherwise.

=Robostix Voltages=

The ATmega128 processor is run at 5 volts, and there are 3.3v to 5v converters on the board for connecting to the gumstix. The robostix includes a total of four voltage regulators (in particular, the MIC5219). Unlike the regular gumstix daughtercards, the robostix can deal with voltages upto around 9v.

Because of the way the voltage regulators are wired, power must be applied to the robostix board. Normally, power can be applied to any daughtercard with a power jack, but when using the robostix, power must be applied to the robostix board.

One of the 4 voltage regulators provides 500mA to the gumstix and any other connected boards. Some CF cards, combined with the gumstix, require more than 500mA of current. In this situation, both the CF board and the robostix must be powered. The CF board should be powered with a regulated 5v source in this situation.

The Robostix troubleshooting page illustrates the location of the 4 voltage regulators.

=Powering on your robostix=

Most of the sample programs start off by flashing an LED. If you see one of the LEDs flash, and then immediately go out, just as you power on your gumstix, then your robostix has probably been powered off, or is being held in reset, by u-boot.

The following sections describe various ways that you can ensure your robostix is running.

Use the robostix program
Load the robostix_drv.ko module and use the robostix program insmod robostix_drv.ko robostix power on

Use the S10robostix script
You can copy the S10robostix script into the /etc/init.d directory on your gumstix. This will run when your gumstix boots, and manipulate the GPIO lines that connect to the robostix, such that it will be powered on and taken out of reset.

Manipulate the GPIO lines
You can do essentially the same thing that the S10robostix script does by manipulating the GPIO lines:

To power on the the '245 voltage converter: echo "GPIO out clear" > /proc/gpio/GPIO72

To enable the robostix voltage regulator: echo "GPIO out set" > /proc/gpio/GPIO70

To take the robostix out of reset: echo "GPIO out set" > /proc/gpio/GPIO73

Modify your u-boot environment
The Robostix uboot page describes how to modify your u-boot environment such that you can make your robostix start as soon as the gumstix is powered on.