28 Jan 2003 hudson   » (Master)

I've redesigned my controller boards to be more modular and fit in less space. Several folks wanted the inertial sensors to be separate from the microcontroller and servo interface, so I've put them on their own boards. You can see the preliminary files and images, although some changes do need to be made.

I have also been hard at work decoding the Futaba PCM radio protocol. It is far more complex than the PWM pulse train that is PPM and will require a software uart to decode. The important bits are that it uses a 150 usecond bit clock, a 2.7 msec sync pulse and two 120 bit frames.

These frames are then transmitted inverted, including the sync pulses. I suppose if there are any errors the frame is to be discarded. You can see this clearly in an image of the PCM frames. Each raster line is the four frames. The source code for generating this is in plotpcm, which uses the output of the microcontroller running onboard/rev2/pcm.c.

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