Genie Microcontroller Homework

-
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Is Not an Emulator) on my workshop computer downloaded from the Linux Mint repository, but this turned out to be wildly out of date, so I uninstalled it and and downloaded the latest version directly from Wine HQ.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.


Comments

Post a Comment

Popular posts from this blog

Update on the touch monitor

-
This is tantalising... I found some data on driver chips used on these low-cost monitors and some of them have an I2C connection for sending pixel data directly to the screen. This may be to allow text or graphics overlay. Anyway the chip on my 7" screens is an AR05C-LF and there are millions of these in stock in the far east, but I can't so far find a data sheet for this chip or its sibling the AR05CA-LF. Being able to send digital pixel data via I2C directly to the screen would be, well, brilliant.
Read more

Apple iPad SSH Connection to Linux Laptop

-
Image
I was given this older Apple iPad a while back and was looking into installing Linux on it. Options are limited, but it is possible to install a shell to the iPad and run command line stuff.  SSH is always a bit of fun so I logged into my Linux Mint laptop remotely for a giggle. It was interesting running a few simple commands from the iPad. My cheapo Bluetooth keyboard came in very useful although I discovered that the iPad's OS version predated mouse support so the trackpad didn't work. Going a step further, I got my Raspberry Pi going again and was able to install VNC on the iPad and remotely control the Raspberry Pi's desktop. Could be useful! I'm also looking at fitting a small heatsink and 5-volt fan (recovered from a broken laptop) to the Raspberry Pi and over clocking it to 1GHz.
Read more

Skoda Rapid Heater Re-circulation Motor Repair

-
Image
In the autumn of 2018 the heater re-circulation motor (I'll refer to this as the HRM from now on) in my 2015 Skoda Rapid decided to fail. It had been making a grinding and clicking noise for a while and I had asked the local Skoda dealer to look into this during a routine service, which they didn't, but more on that later. The problem was that the motor failed in the re-circulate setting so the interior of the car steamed up very quickly and the windscreen couldn't be de-misted. Putting the air-conditioning on was a short-term solution up until the outside temperature dropped below 10 Celsius and that stopped working! There isn't a lot of information online about the Rapid because it is a less common model than other Skodas, but it shares a lot of design with the Fabia and Octavia so it wasn't too hard to get diagrams showing where the motor was and how it works. To get at the HRM I had to remove the glove box (7 Torx screws) and the heater motor (5 Torx screws),
Read more