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Replacement board for Casio Calculator Watches using the CC430F6147

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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 The wiki's DeveloperGuide page might be particularly handy.

73 from Knoxville,


POCSAG Goodwatch Photo

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 Morse and GFSK transmitters, as well as an OOK transmitter that will command cheap remote-controlled relays. It has a frequency counter. 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. P25 and DMR support might come soon.

Additionally, we've written our 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.

Hardware Status

Our replacement board is based around the CC430F6147, which combines an MSP430 microcontroller with an LCD controller and a sub-GHz radio. Thanks to pin compatibility, our fancy linker scripts produce a firmware image that works just as well on the older CC430F6137 chip.

The GoodWatch30 is our current hardware revision, with filters that run from 300 MHz to either 500MHz or 915MHz. The GoodWatch20 family had narrower filters at 433MHz, but is still supported.

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 happily use that project's energy monitor utility for measuring our power budget.

Elektronika-1 is Benjamin Sølberg's replacement board for the Soviet Электроника-1 watch, based on an MSP430FR2433.

Sensor Watch is Joey Castillo's ATSAML22 replacement board for the Casio F-91W. He adds a backlight, and a 9-pin flex PCB allows you to add a custom sensor to the watch, rather than have one built into the board.

The CharlieWatch from Trammell Hudson is a nice little fork of the GoodWatch that uses a charlieplexed array of LEDs instead of a Casio watchcase.

iceSIO matches the same Casio 3208 casings as the GoodWatch, but uses a PIC16 platform with accelerometer, compass and environmental sensors.

FaradayRF is a CC430 radio board intended for amateur use, with a 500mW amplifier and GPS receiver. Their radio chain is far more carefully designed than ours, but in time, we hope that the two projects will communicate with each other.

openchronos-ng-elf seems to be the most recently maintained firmware for TI's OpenChronos devkit, which uses the CC430F6137. See Adam Laurie's ChronIC project for an early example of sniffing OOK traffic and replaying it from a watch.

F91 Kepler is an OLED and BTLE replacement for the Casio F91W module. It uses a CC2640 and has some rather good documentation.


Replacement board for Casio Calculator Watches using the CC430F6147







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