13 Jan 2002 hudson   » (Master)

I made good progress today on the realtime board. First, the good news:

  • Crystal clock problems have been resolved.

    Rather than frying another chip with uisp, I tried PonyProg2000. It's an IDE style programmer for just about every serial chip on the market and has GPLed some versions of the code. The latest is a binary-only release for Linux that includes suppot for the Mega163. Download it from:

    http://www.lancos.com/prog.html

    Based on John Cunningham's suggestion, I set the CLKSEL fuse bits to 1011 and the little board is now screaming along at 4.0 Mhz or so. The toasted chip is still in paperweight mode. I haven't tried resurrecting it yet.

  • Servo output works and is jitter free.

    Nothing really had to change. The 163 does have a direction control for Port C, while the 103 does not. Simple code change to set DDRC for output. I've tested it with the Futaba S3001 and HiTec HS-81 servos from our two prototype aircraft.

  • Accelerometer sampling looks good and fairly smooth.

    The faster clock rate helps give us a bit more precision. I've added a very simple weighted average to the sampling. The response is fairly good.

The Bad news:

  • Analog voltage sampling is still hosed.

    No matter what I try I can not get the internal voltage reference to come online. The bandgap is enabled (BODEN) and I can sample it and confirm that it is at 1.22 volts. But the reference voltage will not change from AVcc = 5.0V. Any ideas? You can see the ADC code here:

    http://autopilot.sourceforge.net/cgi-bin/source?onboard/avr/adc.c

  • The board is UGLY.

    All those jumpers and cut traces offend me. Rev 1.0 is a mess and needs to be cleaned up. The boards are available if anyone wants one. Just add parts.

  • Murata gyros will mess it all up.

    I'll have to redesign the board, but that is life.

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