Dec 18 2009
CamControl – Operating System
I have already done some work on the CamControl software. As always, I use Linux as my development host. I use avr-gcc to compile my software and avrdude to download it via the ISP. Unfortunately I don’t have a JTAG which kind of complicates development, but with such a simple controller I can live without it.
A few words why I have chosen the Olimex AVR-MT-128 board. This board has all the major features I was looking for in a rather compact package:
- LCD (unfortunately without backlight)
- Five keys for navigation
- A LED (which turned out to be wired parallel to the relais, so it’s rather not so useful, as the relais triggers whenever the LED is toggled)
- 16-bit PWMs for servo control (8-bit is not enough for smooth servo movement)
- Buzzer for notification when a job is done
- Plenty of IOs for additional stuff (rotary encoder, AF and shutter control, additional LEDs etc.)
- 4Kb of RAM (should be more than enough)
- 4Kb of EEPROM (nice to persistently store some settings)
- 128Kb Flash (more than enough)
Well, that’s about it. A rather nice board in my opinion. I plan to package it in a nice little enclosure and add a battery. So this could be used standalone without the mechanical construction. Might be useful when I just do timelapses etc. instead of always carring around the panorama construction.
I develop the software as an open-source project, partly because I use open-source components but also because I like the open-source paradigm. The source code repository is hosted on my github account here. I have ported QuantumLeaps QP-nano framework, which is a really nice small event-based operating system for small microcontrollers. I also use avr-libc which offers superb utilities for the AVR microcontroller line. I have already implement a simple keyboard driver and the basics for a menu system. Based on avr-libc I also written a LCD driver. This all works really well so far.
