> 1. What are devices 0x20 and 0x7e?
Device 0x20 is a D/A used on the gumstix board. It controls the core
voltage. I wouldn't mess with it :)
I haven't been able to figure out what 0x7e is, or even if it's a real
device. It doesn't respond to any commands I've tried sending it.
> 2. So, Robostix is a slave to Gumstix and must be running i2c-Boot-m128-1=
6MHz.hex at all times?
Not necessarily. That's just if you want to use the i2c bootloader.
The bootloader allows new programs to be downloaded to the robostix
without requiring the ISP jumpers. If you have multiple robostix, you
can connect them together over i2c as well.
> 3. How do I reach servos, Atmel 1 etc. with I2C? Can I do it through Gums=
tix now or should I still write a code and compile it for Robostix?
You can do it either way. I wrote a wiki page on accessing servos
directly from the robostix:
There currently isn't any code for accessing Atmel-1 UART, but I've
started working on some code to make it show up as a linux serial
port. Right now I'm being distracted by building my robot though...
There is a sample code in SVN for accessing either UART (and the
Flash-LED sample writes strings to both UARTs).
I also wrote a shell script which can control the servos using the
i2c-io program mentioned below. You can find the servo script here:
> 4. After I2C working, can I free Atmel 0 and PXA ST for other needs than =
ISP? Will I2C still work after rebooting?
Yep. Jumpering Atmel 0 & PXA ST is only required for programming the
robostix via ISP from the gumstix. The i2c bus is hardwired.
> 5. Is there a sample code to control Robostix through Gumstix through I2C=
Check out this page:
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