Well, this is a first for us…our initial prototype design for an ESP32-S3 "RGB TTL" display driver board didn't work perfectly the first time!!@!?? j/k that's like Tuesday for us…so back to the drawing board. We won't try driving the TFT from the octal PSRAM dedicated pins (35, 36, & 37 natch), which means our pin usage got squeezed out since we needed them for all the hardware and button interfacing. So we slapped on an xCA9554
https://www.digikey.com/short/qpmrj929
- picked because it's the same i2c expander used on the official EV kit
https://www.digikey.com/short/nbbjr3nh
and its pretty cheap. Now, the expander handles the three TFT SPI initialization pins, TFT and touch reset, a basic backlight on-off, and the two side buttons. That leaves us 6 GPIO free: a full SPI set and two analog pins. We will share the neopixel with the UF2 bootloader double-tap detect. Will it work? We'll find out!
