MCU Display Pin Function Analysis

With 8 or 16 data lines plus control signals, the MCU interface (8080/6800) is based on register read/write architecture. Commands and data can be written directly by controlling the WR/RD/CS/RS signals from the microcontroller. The MCU interface uses parallel transmission (8-bit or 16-bit), transmitting one byte or one word (bit) at a time, resulting in higher bandwidth. It eliminates the need to generate complex horizontal and vertical synchronization signals (such as HSYNC/VSYNC/DE/PCLK in an RGB interface). Software typically only needs to provide write commands and write data functions, making it very intuitive and easy to debug.

Compared to the SPI interface, the MCU interface can be more than 3 times faster under the same clock speed.

SPI interface: 50MHz × 1bit = 50Mbps   

MCU 16-bit interface: 10MHz × 16bit = 160Mbps 

The WR signal of the MCU interface has a lower frequency (a few MHz to tens of MHz), resulting in better signal integrity and stronger anti-interference capabilities. The RGB interface requires a pixel clock (PCLK) of tens or even hundreds of MHz, which is prone to electromagnetic interference.

1-10 feet :

• DB0 to DB3: Low bits of the data bus (DB0 is the least significant bit), used to transmit display data.
• GND: Ground pin.
• VCC: The power supply is usually 1.8V-3.3V.
• CS (Chip Select): Chip select signal, active low, used to enable or disable screen control.
• RS (Register Select): Register select; high level for data register, low level for instruction register.
• WR (Write): Write enable signal. A low level allows data to be written.
• RD (Read): Read enable signal. A low level allows data to be read.

11-20 feet :

• NC (No Connection): Pin not connected.
• TP_X+/TP_Y+, TP_X-/TP_Y-: Touch screen coordinate signal pins.
• LED_VCC: Positive terminal of the backlight power supply, providing voltage for the LED backlight.
• LED1_GND to LED4_GND: Grounding pins for backlight LED K, which must be used in conjunction with LED_A.

21-30 feet :

• NC: (No Connection): Pin not connected.
• DB4至DB17：数据总线高位（DB4至DB7为常规数据位，DB10至DB17可能用于扩展或特殊功能）。

31-37 feet :

• RESET: Reset signal, low level resets the screen controller.
• VCC (repeated): Positive power supply, may be in a different voltage range (needs confirmation).
• GND: Grounding pin.
• DB5 to DB7: Intermediate bits of the data bus, used for transmitting display data.