2020-08-18 PCA9539R IO expander validation notes

Owned by Ryan Dancy
Aug 18, 2020
1 min read

Participants: @Josh Rong (HW) and @Ryan Dancy (FW).

Notes:

  • Josh’s new controller board works and we are able to program it, as confirmed by programming controller_board_blinking_leds.

  • We were not able to get any logging on minicom from the controller board (device /dev/ttyCMSIS, running with minicom -D /dev/ttyCMSIS gave the minicom startup screen, but then nothing).

  • Testing with a multimeter, the PCA9539R smoke test was not able to set GPIO pins on the IO expanders. Manually sending the I2C commands with the I2C smoke test was also unsuccessful.

  • Upon investigation, Josh switched the SDA and SCL pins during design, which is why I2C comms were unsuccessful.

Resolution: hardware issue with the SDA and SCL pins switched, Josh is working on it.