Genie Microcontroller Homework

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My son came home at the end of term with his technology electronics project, which unfortunately didn't work. I'm not sure what sort of a mark or grade he got for this, his end-of-term report hasn't appeared just yet. Anyway, I thought it would be fun to have a go at fixing it for him.

The project is based on a Genie C08 microcontroller which is a PIC 12F683 8-pin running custom firmware, essentially a serial bootloader. The Genie software is a free download which was handy, but I didn't have a Genie programming cable and didn't fancy spending £15 buying one when I thought I could probably bodge a programmer using parts I already have.

The first issue was getting the Genie Programming software running on Linux. I had a version of the Wine Windows abstraction layer (Wine Is Not an Emulator) on my workshop computer downloaded from the Linux Mint repository, but this turned out to be wildly out of date, so I uninstalled it and and downloaded the latest version directly from Wine HQ. I needed to do this to make sure that the Genie software could communicate with a mapped serial USB port, but with the latest version of Wine this turned out to be very straightforward.


Getting the software to communicate with the Genie C08 required a bit more ingenuity. The official Genie cable uses an FT232RL USB-to-TTL serial IC and inverts the signals, something that I couldn't do with the cheaper CP2302 IC used in the adaptor above. The solution was to add in a 74LS00 hex TTL inverter IC.


My son's soldering is not at all bad, but he told me he was rushed which explained why some of the resistors were in the wrong place, the transistor was back-to-front and an LED was connected with reversed polarity (ouch!). A schematic from the Genie website helped me get everything in the right place and hey presto the software and the Genie started talking to one another. After testing the board with a LED flash program, which is the microcontroller equivalent of 'Hello World,' I used some built-in code to get the board singing Jingle Bells. I won't insult anyone with a video of that!

So what have I learned? I am going back to Bert van Dam's PIC book to look at what is involved in adding serial bootloaders to some of the PICs I have stocked to make them easier to program, like the Arduino or Genie. I also ordered an FT232RL-based USB-to-TTL serial adaptor on eBay to play with.


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