Talking NIBL at 1200bd via a modified Chatpad

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Talking NIBL at 1200bd via a modified Chatpad

Post by Phil_G »

I'd been looking for a miniature keyboard and learned of Giancarlo Todone's Xbox 360 Chatpad mod from thirteen years ago, which replaces the internal PIC16F833 firmware of the Chatpad, turning it into a straightforward serial ASCII device. This was exactly what I needed and I spent a long time trawling dead links, removed content, no-longer-in-service servers, and along the way found a few lost enthusiasts in the same situation. Thirteen years is a long time and some really good stuff often fades from existence as websites, ISPs and interest comes and goes. Old projects can completely disappear and tracing them can be a trudge.
Eventually I did find Giancarlo's Chatpad hex file, but equally difficult was finding a non-potted Chatpad, ie one with an accessible PIC16F833 which I eventually found on my third ebay purchase. Not sure what to do with the two unsuitable ones :D

The ideal Chatpad for this mod appears to be from 2007, so its pot luck when buying used. The replacement firmware is hard-coded to 4800 baud, and for my NIBL board I needed 1200 baud, so set about disassembling and manually patching the hexfile. The result is a working 1200 baud version of the code. I removed the protruding earphone jack and the multi-connector so the board lays nice and flat:


Please note that the keyboard firmware is Giancarlo's work, all I have done is a small edit of his hex file. A hack of a hack! The 1200 baud version is attached. It might be my Chatpad - after all its 13 years old - but whilst it works well, I do get occasional keybounce. Its an unavoidable compromise if you need a really tiny keyboard - and it does match the 4" screen perfectly :D

One change I might make is to invert the 'shift' key as NIBL uses only upper case and having to hold 'shift' for every character entered is a pain, and prevents one-finger typing. Or maybe get a 'shift-lock' working.

Edit: Done.
I've included a version that I've patched to invert the 'shift' function, eg pressing 'A' gives 'A' and pressing shift-A gives 'a' etc
Sorry no code, I dont have any, I only have the hex file.

Edit: I've since bought another Chatpad, as I said its pot luck which version you get, and you dont know until its been completely dismantled. Luckily this was the PIC version so I now have a spare which is always good when tinkering, with the ever-present risk of blowing something irreplaceable up ;)
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