| PIN NO. | SYMBOL | DESCRIPTION | FUNCTION |
|---|---|---|---|
| 1 | 5V | 5V power supply | When powered from 5V supply, Pin 1 & Pin 2 as power input, Pin 33 & Pin 34 provide 3.3V output. |
| 2 | GND | Ground | GND |
| 3 | D0 | Data lines | D0-D15 |
| 4 | D1 | ||
| 5 | D2 | ||
| 6 | D3 | ||
| 7 | D4 | ||
| 8 | D5 | ||
| 9 | D6 | ||
| 10 | D7 | ||
| 11 | D8 | ||
| 12 | D9 | ||
| 13 | D10 | ||
| 14 | D11 | ||
| 15 | D12 | ||
| 16 | D13 | ||
| 17 | D14 | ||
| 18 | D15 | ||
| 19 | CS | LCD chip select | Low active |
| 20 | RS | Instruction/Data register selection | RS = 1 : Instruction Register RS = 0 : Data Register |
| 21 | WR | Write | WR = 0, RD = 1 |
| 22 | RD | Read | WR = 1, RD = 0 |
| 23 | RESET | Reset the controller chip | Low active |
| 24 | NC | Not connect | Not connect |
| 25 | BLVCC | 5V or 3.3V | Backlight VCC |
| 26 | BLGND | Ground | Backlight GND |
| 27 | BLCNT | Backlight brightness adjustment | Control the backlight brightness via PWM |
| 28 | TP_IRQ | Touch screen interrupt | Low level while the touch screen detects pressing |
| 29 | TP_CS | Touch screen chip select | Low active |
| 30 | TP_SCK | Touch screen SPI clock | connects to SPI SCK |
| 31 | TP_SI | Touch screen data input | connects to SPI MOSI |
| 32 | TP_SO | Touch screen data output | connects to SPI MISO |
| 33 | 3.3V | 3.3V power supply | When powered from 3.3V supply, Pin 33 & Pin 34 as power input, Pin 1 & Pin 2 keep NC. |
| 34 | GND | Ground | GND |
Remaining pins are NC on the 2-header variant, while the SD variant uses the following additional assignments (unproven -- I probed continuity and cross-checked with published SD pinouts).
| Pin No. | Symbol | Description | Function |
|---|---|---|---|
| 35 | SD_DO | SD card data out | SPI output |
| 36 | SD_CLK | SD card data clock | SPI clock |
| 37 | SD_DI | SD card data in | SPI input |
| 38 | SD_/CS | SD card chip select | Active low chip select |
