Howdy y'all,

This is a side project of mine to build a replacement circuit board for the Casio 3208 module, used in the Casio CA-53W and CA-506 calculator watches. It is not compatible with the 3228 module used in the Databank watches, which have four external buttons instead of two. As a side project, it has no warranty whatsoever and you shouldn't use it for anything.

In the rare case that you find this project to be useful, you owe me a pint of good, hoppy pale ale. All license to use this project is revoked if you try to pass off a pilsner instead.

In addition to the source code, there is handy documentation in the wiki and a general interest website at goodwatch.org.

73 from Pizza Rat City, --Travis

Software Status

Our firmware is freely available in this repository, compiling with the standard MSP430 compiler packages that ship with Debian. It consists of a Clock, a Stopwatch, an RPN Calculator, and a Hex Memory Viewer with Disassembler, all written in C. It compiles in Debian with all of the MSP430 packages installed.

On watches with a radio, we have a basic Morse transmitter and GFSK beacon transceiver for now, with other radio applications on the way. The radio is accessible from a host computer over the UART for building base stations and repeaters, or for rapidly prototyping radio applications in Python.

Additionally, we've written out own client for the CC430's BootStrap Loader (BSL). You might find it handy for other projects involving that chip, or other MSP430F5 and MSP430F6 chips without USB. You will need to be a member of the dialout group to flash the firmware.

Firmware documentation can be built with Doxygen.

Hardware Status

Our replacement board is based around the CC430F6137, which combines an MSP430 microcontroller with an LCD controller and a sub-GHz radio.

The initial version, the GoodWatch10, lacks a radio but supports all other features, such as the RPN calculator, hex editor, and disassembler. Assembly of the GoodWatch10 is no longer recommended, as the PCB requires a bit of whittling to fit the case.

The GoodWatch20 is now our primary target, featuring minor corrections to layout and a functional radio. The radio is in active use, and the filter chain is verified to work.

The GoodWatch21 will be manufactured in early 2018 with a wider filter and other radio modifications.

See BOM.txt in the hardware directories for a parts list, and the wiki for an assembly guide.

Related Projects

Pluto is a replacement PCB for the Casio F-91W that is also based on an MSP430. We are jealous of that project's simulator and energy monitor utility.

FaradayRF is a CC430 radio board intended for amateur use, with a 500mW amplifier and GPS receiver.

openchronos-ng-elf seems to be the most recently maintained firmware for TI's OpenChronos devkit, which uses the CC430.