I've been working my way through the subsystems, testing everything and writing software as I go. So far, pretty much everything works as designed, with only a few minor ECOs. Most of the changes are tweaks to resistor values to adjust edge times and LED brightness. The only design "flaw" so far is that one of the comparators I'm using is open collector, and I thought it was push-pull (the other one *is* push-pull), so I need to add some pullup resistors. (yes, Dan, I'll be using that grid of pads you suggested ;)
As an amusing aside, the five MCUs have serial consoles :-) The gumstix talks to the MCUs using i2c. However, the in circuit programming using some GPIOs and a multiplexed serial port. So, I can have the programmer (which runs on the gumstix) stay connected to the serial port after programming, and the MCU can print to it. I can only monitor one at a time, but it's handy to have printf() when debugging. I'll probably add pull-ups to the /RESET lines on the MCUs so they can run without the gumstix even present. I imagine one could write a functional furnace controller just using the five MCUs talking to each other over i2c (the R8Cs can be i2c masters or slaves), as the R8C-26 has 32k of flash and 1.5k of ram, enough to run a supervisor (the four R8C-1Bs have 16k of flash and 1k of ram). _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
