README-DEVICE.md

Connections

Serial

• UART0 (GP0/GP1) - connected to mux on CH340C on picocalc
• UART1 (GP8/GP9) - connected to M_UART3 aka Serial1 on picocalc mcu. Default mcu firmware writes pmu debug logs to this.

I2C

• I2C1 (GP6/GP7) - I2C bus connected to picocalc keyboard/pmu mcu M_I2C1

LCD

• GP10 - SPI1_SCK
• GP11 - SPI1_TX
• GP12 - SPI1_RX
• GP13 - SPI1_CS
• GP14 - LCD_DC
• GP15 - LCD_RST

Audio

GP26/GP27 - PWM_L/PWM_R on picocalc audio circuitry

TF Card reader

• GP16 - SPI0_RX
• GP17 - SPI0_CS
• GP18 - SPI0_SCK
• GP19 - SPI0_TX
• GP22 - SD_DET

PSRAM

• GP2 - RAM_TX
• GP3 - RAM_RX
• GP4 - RAM_IO2 - quad mode
• GP5 - RAM_IO3 - quad mode
• GP20 - RAM_CS
• GP21 - RAM_SCK

Note that all except the CS are exposed to expansion/jumper block.

Expansion Port/Jumper block

• GP2 - Also connected to PSRAM
• GP3 - Also connected to PSRAM
• GP4 - Also connected to PSRAM
• GP5 - Also connected to PSRAM
• GP21 - Also connected to PSRAM
• GP28