Digging further I found that when I run adafruit-pitft.py to set up the board, it inserts the following dtoverlay call into /boot/config.txt. digging a bit further, I see that this particular overlay disables the two spi ports. Not good.
Code: Select all
dtoverlay=pitft28-resistive,rotate=270,speed=64000000,fps=30
I am trying to get the pitft setupscript to run properly because checking the various pins feeding the tft, it seems to me that when I display something on the display, something in the firmware is tying the CLK pin (pin 4 on the SPI-side) high. I have a nearly identical setup on a breadboard with another Rasp Pi 0W and 2.8 screen, etc, and it works fine.
I have buzzed out the circuit board on which I am building my device and it checks out: routing is fine, no cold solder joints, no bridging, no short circuits, etc.
Swapping the two displays from one to the other yields same results: good display does not work in the circuit board, and the previously not working display works well on the breadboard.
Ideas and/or suggestions?