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Fadecandy Test Jig
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This is a simple one-off test fixture that's designed to facilitate in-circuit debugging of the Fadecandy firmware, and doing reliable low-volume production.
My prototype consists of:
* An ugly hand-wired perfboard
* 0.1"-spaced pogo pins which connect to the Fadecandy board's "hacker port" as well as its output header
* A standard ARM JTAG header for firmware development using an external JTAG adapter
* A 2-LED string of WS2811 LEDs, for verifying the timing of the Fadecandy outputs
* A Teensy 3.0 board which coordinates production and testing tasks
The board is intended for two separate use cases:
* During firmware development, it's a simple breakout board for the JTAG port
* During low-volume production, the Teensy installs firmware and performs electrical testing
This board is a work-in-progress. This directory contains Teensyduino sketches which run on the onboard Teensy. More information about the hardware will be included later.
Hardware tidbits
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* JTAG port uses 10K pull-up resistors to Fadecandy's 3.3v rail on all signals.
* Pogo pins are 2x Digi-Key part ED8178-16-ND
* Big green button next to pogo-pins to initiate programming/test
Teensy 3.0 pin assignment
-------------------------
Pin | Description
--- | ----------------------------------
Gnd | Shared ground
Vin | +5V power for testjig itself
0 | Teensy RX, Fadecandy TX
1 | Teensy TX, Fadecandy RX
2 | To ground via green button
3 | Fadecandy TCLK (SWCLK)
4 | Fadecandy TMS (SWDIO)
Testjig Firmwares
-----------------
* `production`
* Programs bootloader and initial firmware image
* Runs electrical tests
* Communicates with the DUT processor using Serial Wire Debug
* `serial_passthrough`
* Teensyduino sketch
* Appears as a USB serial port device
* Passes through access to the DUT serial port
* When the green button is held, acts as a loopback for the DUT serial port, as one way to enter FC-Boot.
Contact
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Micah Elizabeth Scott <<micah@scanlime.org>>