Week #10 Dabbling with Steppers and Servos, timing signals and interrupts

This week was week #10 at GSoC.

So this week we got a new assignment from prpplague ! Design a board/cape that you can use with the Black to learn about the different forms of interfaces that are available with it.

So for example, the Bacon board is a good starting point to learn how to use PWM and ADC because it has a slider pot as well as a RGB led on it. Similarly, to use and learn about SPI, I2C, CAN, Serial we can have a cape that has all these interfaces in a usable format with the right connectors. hatguy had the idea of including an audio out too.
The EEPROM will take care of loading the appropriate pin mux. I have created a project here. Will have a working sketch by next week hopefully.
Apart from working on this, I bought a stepper and a servo motor.

For servo, the arduino library is implemented using interrupts, which I haven’t understood completely yet but seems like too much of an effort to replicate on Linux. I have a few ideas on how to have an alternate implementation, but the thing is that we do need interrupts in the Arduino core which haven’t been implemented yet. So maybe I can get two things if I stick to interrupts.
Stepper on the other hand seems fairly straightforward. It doesn’t require any external avr specific libs, so I can use the libs as is under Linux. I have some issues with the stepper I got, but it’ll most probably done by tomorrow if not earlier.

PS: I am attending PyCon India this weekend, and was thinking of giving a simple demo of OpenCV+Tornado webserver+Adafruit-BBIO there (thanks to Koen for helping me out with the python-opencv package). Hopefully I’ll get a slot for a lightning talk and can brag the BBB’s capabilities.
Have created a repo where I keep simple demos for BBB which I can use when I go for a conf or at a workshop.


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