Robostix SPI
From GumstixDocsWiki
The current robostix board doesn't provide easy access to the SPI pins when you're using the robositx in standalone mode. This page documents various places that small 30 gauge wire wrap wire could be soldered to pick up those signals.
On the ATMega 128 itself, the pins are:
- 10 - SS
- 11 - SCK
- 12 - MOSI
- 13 - MISO
Pin 1 is in the top left corner and pin 16 is in the bottom left (so it's probably easier to count down from 16 to find the right pin).
These are probably the 4 easiest spots to solder to. Unfortunately, the vias on the robostix board are too small for 30 gauge wire, and they're also covered in solder resist (this is the stuff that makes the traces look green).
It's possible to pickup SCK from the ISP connector.
It's also possible to pickup all of the signals from the U$52 and U$54 chips, however the pin spacing on these chips is finer than that on the ATMega and they're harder to get to, so I won't bother mentioning the pin numbers.
Note: When a gumstix is plugged into the robostix, the gumstix is the SPI master, and the robostix is the SPI slave. Never try to use the SPI line from the ATMega as a master when the gumstix is plugged in.
further reading
- Sample code/C/SPI has some details on the SPI code inside the gumstix that talks to the robostix.
