So I've been trying out an AT42QT2120 as a "wheel" interface to replace a "knob". My demo code worked on a Mikroe development board, but doesn't work on my own board.
I've got some ideas to work through, but I'd like to know: does the "AT42QT2120" use "clock-stretching" to slow down the I2C interface, as one big difference between my successful test and the failure is the full test used hardware I2C, and the failed test uses a minimal soft I2C driver that doesn't support clock-stretch. The minimal driver was intended to support I/O expanders that never output on SCL.
I haven't seen it stated, but I get the impression the part may be a mask-programmed microcontroller, and therefore subject to bus timing limitations.