Work Log
2011-08-26
Have been trying to get FreeRTOS to work but I seem to be crashing the stack, at least when running it in simavr.
Some notes to self:
| Address | |
|---|---|
| 0x0000 - 0x001f | 32 registers |
| 0x0020 - 0x005f | 64 I/O registers |
| 0x0060 - 0x00ff | 160 ext. I/O registers |
| 0x0100 - 0x02ff | Internal RAM |
The program memory map is from 0x0000 -> 0x07ff.
Tricks learned
Commands for inspecting the generated ELF file
- avr-objdump -S -d -t -h main.axf
- avr-size main.axf
2011-08-22
Yay, the motor was delivered today. Time to bring out the oscilloscope and look at some BEMF waves. Need to find a small motor to run the motor at a constant RPM.
Found a nice paper on a physical model for brushless motors. Might be nice to model the motor to generate test input and output.
http://web.mit.edu/scolton/www/SCThG.pdf
2011-08-10
Fixed some nits on the 3d model generator
Ordered 50 MOSFETs and 10 AVRs so most of the hardware should be here in a few weeks, yay.
2011-08-08
Completed the TQFP generator, the boards is looking even better even if there's a bunch of components missing.
Found a useful datasheet for the pin headers that can be used to generate models similar to the TQFP: http://www.adam-tech.com/pg204-206.pdf
2011-08-07
Worked even more on the PCB design today. Wanted to try out EagleUp as it seems quite nice and have a usable workflow between Eagle and SketchUp. However, EagleUp doesn't have a big component library so I had to make some. I started creating a model for the Atmega which was rather easy in SketchUp. SketchUp really is a simple modelling tool. However, the inner programmer came out and so I started to write a SketchUp plugin for generating TQFP packages. Yay.
2011-08-06
Published my stuff on github.
External References
Notes
ESC / Brushless DC motor control
- General description of now brushless motors are controlled: http://robot.avayanex.com/?p=147
- Build a Versatile Miniature High-Rate ESC with BEC and Brake http://www.stefanv.com/electronics/escboth.html
- PIC Processor and DC Motor Control Reference http://www.oocities.org/glenn65535/rc/rc.html
- http://www.flyelectric.ukgateway.net/avr_ff_timer.htm
- A very nice design: http://home.versanet.de/~b-konze/blc_4428/blc_4428.htm
- http://ww1.microchip.com/downloads/en/AppNotes/00857a.pdf
- A new technique for driving brushless motors. Also includes a thing on using current spikes to sense position. http://www.thic.org/pdf/Oct01/MEII-JGriffitts.pdf
- AVR444: Sensorless control of 3-phase brushless DC motors http://atmel.com/dyn/resources/prod_documents/doc8012.pdf
- How to use comparators for zero-crossing detection: http://sound.westhost.com/appnotes/an005.htm
Possible Parts
- IRL2203 suppliers:
- International Rectifiers's list of DC motor/Industrial Applications products: http://www.irf.com/product-info/hexfet/fs10162.html
Random links
- http://norbique.rchomepage.com/esc/parts.htm
- Buffer MOSFETs: http://ww1.microchip.com/downloads/en/DeviceDoc/21425b.pdf
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