The M9's variant.h defines ST7789_CS, so TFTDisplay.cpp compiles its
ST7789 LGFX branch, which reads SPI_FREQUENCY for the panel write clock
(SPI_READ_FREQUENCY, its pair, is already in variant.h). The flag was only
set in the -tft env, so `build (thinknode_m9, esp32s3)` has failed on
develop since the board landed in #10908:
src/graphics/TFTDisplay.cpp:504:30: error: 'SPI_FREQUENCY' was not
declared in this scope; did you mean 'SD_SPI_FREQUENCY'?
Move the flag up into thinknode_m9_base, keeping the 75 MHz the -tft env
already used for the same panel and matching the SD card's 75 MHz on the
bus they share. The -tft env inherits the base flags, so device-ui's
LGFX_GENERIC.h - which falls back to 20 MHz when the macro is absent -
still sees the identical value.
Ben Meadors
9fcb289643