"Analog" watch with 60+12 Charlieplexed LEDs. Based on Travis Goodspeed's GoodWatch21 schematic, using the CC430F5137IRGZR CPU, which doesn't have the LCD controller of the CC430F6xxx in the GoodWatch. There are also pads for a six pin EZfet cable with pogopins for programming or serial communication.

v0.2 works, although it has no radio parts. It is exactly 1 square inch of PCB and should fit in a 38mm or 36mm case.

v0.1 works, although the radio parts have not been tested. It is a slightly larger board and fits in a 40mm case.

Charliewtch schematic

Building the firmware

Note: some other system packages (boost libraries?) might also be needed.

First, get the toolchain (msp430-gcc):

sudo apt install gcc-msp430 mspdebug

Then the all-important lib file (from https://www.ti.com/tool/MSPDS):

sudo apt install libhidapi-dev
mkdir MSPDebugStack
wget https://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/MSPDS/3_15_1_001/export/MSPDebugStack_OS_Package_3_15_1_1.zip

Copy in the hidapi header (WTFBBQ):

cp /usr/include/hidapi/hidapi.h ThirdParty/include/

Copy the following into a file 'hidapi.patch', so we can use the system hidapi library:

--- Makefile    2020-12-18 18:01:18.602942502 +0100
+++ Makefile.new    2020-12-18 18:02:58.472096541 +0100
@@ -123,7 +123,7 @@
 OBJS := $(patsubst %.cpp, %.o, $(SRC))

 all: $(BSLLIB) $(OBJS)
-   $(CXX) $(CXXFLAGS) -shared $(OUTNAME)$(OUTPUT) -o $(OUTPUT) $(OBJS) $(HIDOBJ) $(LIBDIRS) $(BSTATIC) $(STATIC_LIBS) $(BDYNAMIC) $(LIBS)
+   $(CXX) $(CXXFLAGS) -shared $(OUTNAME)$(OUTPUT) -o $(OUTPUT) $(OBJS) -lhidapi-libusb $(LIBDIRS) $(BSTATIC) $(STATIC_LIBS) $(BDYNAMIC) $(LIBS)
    rm -f $(STATICOUTPUT).a
    ar -rs $(STATICOUTPUT).a $(OBJS)

Then apply and make:

patch < hidapi.patch
make

Finally, build and flash the firmware:

git clone https://github.com/osresearch/charliewatch.git
cd charliewatch/firmware
make
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:`pwd`../../MSPDebugStack/
mspdebug tilib "prog charliewatch.elf"

Programming cable

From the top of the v0.1 board:

• RST / TDIO
• RXD on programmer
• TXD on programmer
• VCC
• TST / TCK
• GND

v0.2:

• greem
• white
• blue
• purple
• gray
• black

There is also a four-wire setup that might simplify the wiring. Travis documents it and the power consumption here: https://github.com/travisgoodspeed/goodwatch/wiki/EnergyTrace

Bricked Launchpad

If you brick your launchpad by running Energia under Linux, it will no longer program the Charliewatch. The other weirdness is that tilib can detect the device, but can't write to it unless run as root.

Energy Trace

• libmsp430.so: https://dlbeer.co.nz/articles/slac460y/index.html
• https://github.com/carrotIndustries/energytrace-util
• Have to update path to MSP430.h from the slac/DLL430_v3/include directory