NuttX RTOS on PicoCalc

[JackCarterSmith]

@shtirlic

PS I guess we can use PSRAM as framebuffer?

320 × 320 × 2 bytes × 30 fps = 6.14 MB/s
320 × 320 × 2 bytes × 45 fps = 9.22 MB/s
320 × 320 × 2 bytes × 60 fps = 12.29 MB/s

We’ve talked a little about this possibility here and here.

The main issue is the maximum LCD SPI speed, which seem to be 62.5 MHz (the maximum for the RP2350, 75 MHz in overclock, can’t say the screen don’t have some artefacts).
So the maximum bitrate shoul be around 7.8 MB/s. 30 or 45 FPS seem feasable, but the 60 is far away unfortunatly.