Tech
19 Sep 2026
6 min read
An SPI microSD Slot Does Not Make an 8-Bit TFT Shield an SPI Display
A 2.8-inch Arduino-style TFT shield can place an LCD and a microSD socket on the same PCB while giving them completely different electrical interfaces. The pin labels are the quickest way to tell them apart. On the shield shown here, the LCD side exposes DB0 through DB7 together with LCD_WR, LCD_RD, LCD_RS, LCD_CS, and LCD_RST. Those are the signals of an 8-bit 8080-style parallel display interface. The labels SD_MOSI, SD_MISO, SD_SCK, and SD_SS belong to the microSD socket.