Python code to generate the LED + circular dial graphic on the web site is here: lm_wxgraphic
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
################################################################################ # # # lm_wxgraphic.py # # # ################################################################################ # # # Generates a graphic for time, temperature, the day's rainfall and # # recent wind statistics from the WOSPi XML file /var/tmp/wxdata.xml # # # # It's almost fully self-contained, no base bitmaps are used but two fonts # # are pulled in. To get this working on a Raspberry Pi You will need to get # # as root: blah blah blah # # -=LogicMonkey=- # # # ################################################################################ |
The ATtiny85-20 SPI authentication key chip sits in the recess of the Davis console:
I programmed and tested it on a piece of breadboard with the RPi itself using a GPIO version of avrdude:
To test, I used the bcm2835 library to access the RPi SPI:
I had one major debug issue – quickly resolved when I noticed that the slow bit banging of SPI by the RPi worked, but the chip in situ didn’t. That was because I hadn’t programmed the CLKDIV8 fuse with avrdude and my code was running at 1MHz instead of 8MHz. I found this with the excellent Saleae Logic analyser – I also found and reported a tool bug to Saleae.
At some point I used the glorious Bus Pirate too – both for SPI testing and 3v3 RS232 level conversion now I come to think of it.
