VCC: VDD(3.3V) GND: GND SDA: SPI data input SCK: SPI clock input CS: SPI chip selection, active at low level BL: backlight control D/C: Display data/command selection pin in 4-line serial interface RESET: Display screen reset, active at low level K1: User key K1 K2: User key K2 K3: User key K3 K4: User key K4 SW1: User key L SW2: User key R S1: Jointed arm