An RP2350-Zero PCB

Author	Message
phil99 Guru Joined: 11/02/2018 Location: Australia Posts: 3319	Posted: 12:56am 30 Mar 2026         Quote   An earlier version of this was the first one I've had where the 680 resistor failed to keep the ILI9488 MISO signal from fouling the SD card. You were lucky, none of my SD cards worked reliably with the 680Ω. At first I used a PN200 transistor which worked well but when others tried different transistors it didn't work. Eventually I found the transistor can be replaced with a diode. Any type with a junction capacitance greater than about 30pF will work such as 1N4004 or 1N5819. The anode goes to LCD_DO and the cathode to MISO via T_DO. The resistor (1.8kΩ to 10kΩ) goes from LCD_CS to MISO via T_DO. They can be mounted directly on the top of LCD pins. Snipping off the LCD_DO pin then makes it compatible with boards intended for other displays. . Edited 2026-03-30 11:01 by phil99