3.3.1 LCD TFT Interface
The baseboard provides a FPC connector with 24 bits of data and control signals to the LCD interface. Other signals are used to control the LCD and are available on connector J26: TWI, SPI, two GPIOs for interrupt, 1-wire and power supply lines.
This connector is used to connect LCD display type TM43xx series, TM5000 series or TM7000 series from PDA Inc. (www.pdaatl.com).
A 50-pin FPC (J26) header is provided on the baseboard to interface the LCD module with 24-bit parallel RGB.
The connector provides two PIOs as interrupts, one SPI and a TWI port to interface the MaXTouch® touch controller or QTouch® button controller embedded on the LCD module.
In order to operate correctly out of the processor with various LCD modules, two voltage lines are available: 3.3V and 5VCC (default). Both are selected by 0R resistors R81 and R83.
The table below describes the pin assignment of LCD connector J26.
| Pin No | Signal | PIO | Signal | RGB Interface Function |
|---|---|---|---|---|
| 1 | ID | PA17 | ID | Shared with SPI_NPCS0 pin 40 |
| 2 | GND | GND | GND | GND |
| 3 | LCDDAT0 | PB11 | D0 | Data line (BLUE0) |
| 4 | LCDDAT1 | PB12 | D1 | Data line (BLUE1) |
| 5 | LCDDAT2 | PB13 | D2 | Data line (BLUE2) |
| 6 | LCDDAT3 | PB14 | D3 | Data line (BLUE3) |
| 7 | – | – | GND | GND |
| 8 | LCDDAT4 | PB15 | D4 | Data line (BLUE4) |
| 9 | LCDDAT5 | PB16 | D5 | Data line (BLUE5) |
| 10 | LCDDAT6 | PB17 | D6 | Data line (BLUE6) |
| 11 | LCDDAT7 | PB18 | D7 | Data line (BLUE7) |
| 12 | – | GND | GND | GND |
| 13 | LCDDAT8 | PB19 | D8 | Data line (GREEN0) |
| 14 | LCDDAT9 | PB20 | D9 | Data line (GREEN1) |
| 15 | LCDDAT10 | PB21 | D10 | Data line (GREEN2) |
| 16 | LCDDAT11 | PB22 | D11 | Data line (GREEN3) |
| 17 | – | – | GND | GND |
| 18 | LCDDAT12 | PB23 | D12 | Data line (GREEN4) |
| 19 | LCDDAT13 | PB24 | D13 | Data line (GREEN5) |
| 20 | LCDDAT14 | PB25 | D14 | Data line (GREEN6) |
| 21 | LCDDAT15 | PB26 | D15 | Data line (GREEN7) |
| 22 | – | GND | GND | GND |
| 23 | LCDDAT16 | PB27 | D16 | Data line (RED0) |
| 24 | LCDDAT17 | PB28 | D17 | Data line (RED1) |
| 25 | LCDDAT18 | PB29 | D18 | Data line (RED2) |
| 26 | LCDDAT19 | PB30 | D19 | Data line (RED3) |
| 27 | – | – | GND | GND |
| 28 | LCDDAT20 | PB31 | D20 | Data line (RED4) |
| 29 | LCDDAT21 | PC0 | D21 | Data line (RED5) |
| 30 | LCDDAT22 | PC1 | D22 | Data line (RED6) |
| 31 | LCDDAT23 | PC2 | D23 | Data line (RED7) |
| 32 | – | GND | GND | GND |
| 33 | LCDPCK | PC7 | PCLK | Pixel clock |
| 34 | LCDVSYNC | PC5 | VSYNC/CS | Vertical sync |
| 35 | LCDHSYNC | PC6 | HSYNC/WE | Horizontal sync |
| 36 | LCDDEN | PC8 | DATA_ENABLE | Data enable |
| 37 | SPI_SPCK | PA14 | SPI_SCK | SPI clock |
| 38 | SPI_MOSI | PA15 | SPI_MOSI | SPI Master OUT Slave IN |
| 39 | SPI_MISO | PA16 | SPI_MISO | SPI Master IN Slave OUT |
| 40 | SPI_NPCS0 | PA17 | SPI_CS | SPI chip select |
| 41 | LCDDISP | PC4 | ENABLE | Display enable signal |
| 42 | TWD | PD4 | TWI_SDA | I2C data line (maXTouch) |
| 43 | TWCK | PD5 | TWI_SCL | I2C clock line (maXTouch) |
| 44 | GPIO | PD1 | IRQ1 | maXTouch interrupt line |
| 45 | GPIO | PC25 | IRQ2 | Interrupt line for other I2C devices |
| 46 | LCDPWM | PC3 | PWM | Backlight control |
| 47 | RESET | nRST | RESET | Reset for both display and maXTouch |
| 48 | Main_5V/3V3 | VCC | VCC | 3.3V or 5V supply (R81/R83 selected) |
| 49 | Main_5V/3V3 | VCC | VCC | 3.3V or 5V supply (R81/R83 selected) |
| 50 | GND | GND | GND | GND |