Smooth video playback on STM32 and ST7735

Parts: - cheap “bluepill“ STM32 ($) - 160x128 ST7735 LCD ($) - SD card Comments: - SD uses faster STM32 SPI1 interface which supports 36 Mbps - Not all SD cards work at 36MBps - Slow card at 18Mbps gives 22-23fps - Fast card at 18Mbps gives 25-26fps - Fast card at 36Mbps gives 33-34fps - SdFat library uses DMA mode for SPI transfer - Big buffer in RAM is used to speed up SPI/DMA transfer from SD - SPI1 is shared between LCD and SD card - Demo videos used here are taken from my older video and are n