PMOD-extended-SPI-TFT

An extended-SPI PMOD that drives a 1.8 inch TFT with an SD card on one board. The extra chip-select lines let both the ST7735S display and the SD slot share a single SPI bus without fighting over the CS pin.

What's on the board

• A 1.8 inch 160x128 TFT with an ST7735S driver.
• An SD card slot.
• An extended SPI PMOD header with two chip selects.
• A blue LED.
• Pull-ups on the SPI lines.

The bus

MOSI, MISO and SCK run to both the TFT and the SD slot. Dedicated chip selects, TFT_CS on CS2 and SD_CS on CS3, let each take the bus in turn. A 100R keeps the edges clean. The second chip select is the whole point of extended SPI; without it the TFT and card fight over one pin.