Board constants

hub.board (hub._board_module) exposes board-specific configuration values as integer or string attributes, set by the C firmware from Board.h at compile time.

import hub
b = hub.board
print(b.BOARD_NAME, b.BOARD_VERSION)

Logical pins and buses

All pin and bus constants in hub.board are logical encoded integers, not raw GPIO numbers. The encoding is:

Logical pin — (chip_id << 8) | pin_index, where chip_id 0 is the native ESP32, other IDs are peripheral chips (PCA9685, SC16IS750, TLA2528, …).
Logical bus — (bus_kind << 8) | bus_number.
-1 (machine.PIN_NONE / machine.BUS_NONE) — pin or bus not wired on this board; accessing it raises OSError.

machine.Pin accepts logical pins directly — the driver decodes the chip and index automatically:

import machine, hub
b = hub.board
if b.BUTTON_PWR_PIN != machine.PIN_NONE:
    pwr = machine.Pin(b.BUTTON_PWR_PIN, machine.Pin.IN)

To build a logical pin or bus at runtime use the helpers from machine:

import machine
# Same encoding as MAKE_PIN(ESP32, 5) in C
pin = machine.MAKE_PIN(machine.PERIPH_ESP32, 5)
# Same encoding as MAKE_BUS(I2C, 0)
bus = machine.MAKE_BUS(machine.BUS_I2C, 0)

Buses

Attribute	Guard	Meaning
`HAS_I2C0`	—	1 if I2C bus 0 is present
`I2C0_SDA_PIN` / `I2C0_SCL_PIN`	`HAS_I2C0`	Logical pins for bus 0 SDA / SCL
`I2C0_FREQ`	`HAS_I2C0`	Default clock (Hz)
`HAS_I2C1`	—	1 if I2C bus 1 is present
`I2C1_SDA_PIN` / `I2C1_SCL_PIN`	`HAS_I2C1`	Logical pins for bus 1 SDA / SCL
`I2C1_FREQ`	`HAS_I2C1`	Default clock (Hz)
`HAS_SPI2` / `HAS_SPI3`	—	1 if SPI2 / SPI3 host present
`SPI2_SCK_PIN` / `SPI2_MISO_PIN` / `SPI2_MOSI_PIN`	`HAS_SPI2`	Logical pins; `SPI2_FREQ` = default speed
`SPI3_SCK_PIN` / `SPI3_MOSI_PIN` / `SPI3_MISO_PIN`	`HAS_SPI3`	Logical pins; `SPI3_FREQ` = default speed
`HAS_UART0` / `HAS_UART1` / `HAS_UART2`	—	1 if native UART present (pins assigned at open time by the port driver)
`HAS_I2S0`	—	1 if I2S bus 0 present (NS4168 audio amplifier)
`I2S0_BCK_PIN` / `I2S0_WS_PIN` / `I2S0_SD_PIN`	`HAS_I2S0`	Logical pins for bit clock / word select / serial data

Peripheral chips

Chip presence is indicated by HAS_<CHIP> (0 or 1). When present, the matching bus and address/CS constants are valid.

Chip	Constants	Purpose
PCA9685	`HAS_PCA9685`, `PCA9685_BUS`, `PCA9685_I2C_ADDR`, `PCA9685_FREQ_HZ`	I2C 16-channel PWM controller
SC16IS750	`HAS_SC16IS750`, `SC16IS750_BUS`, `SC16IS750_CS_PIN`, `SC16IS750_IRQ_PIN`, `SC16IS750_CRYSTAL_FREQ`, `SC16IS750_TX_DISABLE_PIN`	SPI/I2C UART bridge + 8 GPIO
CH9434	`HAS_CH9434`, `CH9434_BUS`, `CH9434_CS_PIN`, `CH9434_RST_PIN`, `CH9434_CRYSTAL_FREQ`, `CH9434_UART{0..3}_TX_DISABLE_PIN`	SPI 4-UART bridge + 25 GPIO
TLA2528	`HAS_TLA2528`, `TLA2528_BUS`, `TLA2528_I2C_ADDR`	I2C 8-channel 12-bit ADC + 8 GPIO
DRV8908Q1	`HAS_DRV8908Q1`, `DRV8908Q1_BUS`, `DRV8908Q1_CS_PIN`, `DRV8908Q1_SPI_FREQ`, `DRV8908Q1_DEVICE_COUNT`	SPI 8-channel half-bridge motor driver (cascadable)
BNO085	`HAS_BNO085`, `BNO085_BUS`, `BNO085_I2C_ADDR`, `BNO085_INT_PIN`	I2C 9-DOF IMU
ST7735	`HAS_ST7735`, `LCD_BUS`, `LCD_SPI_FREQ`	SPI LCD panel (160×128)
NS4168	`HAS_NS4168`, `NS4168_BUS`	I2S Class-D audio amplifier (no control bus)
MCPWM	`HAS_MCPWM`	Native ESP32 MCPWM (motor PWM) peripheral

Subsystems

Attribute(s)	Meaning
`HUB_I2C_MODULE_BUS`	Logical bus used by the hub’s Python-facing I2C module (`hub._i2c`)
`HAS_USB_SWITCH`, `USB_SWITCH_PIN`	USB D+/D- routing switch; logical pin controlling it
`HAS_POWER`, `POWER_ON_PIN`	Power-on control pin
`HAS_POWER_DETECT`, `POWER_DETECT_PIN`	Optional power-present detection pin
`HAS_BUTTONS`, `BUTTON_PWR_PIN`, `BUTTON_UP/DOWN/LEFT/RIGHT_PIN`	Navigation buttons (see Buttons for polarity)
`HAS_LCD`, `LCD_DC_PIN`, `LCD_RST_PIN`, `LCD_CS_PIN`, `LCD_TE_PIN`, `LCD_BACKLIGHT_PIN`	LCD control pins (see LCD)
`HAS_IMU`, `IMU_TYPE`, `IMU_INT_PIN`	IMU chip presence and interrupt pin
`HAS_RGB_LED`, `RGB_LED_TYPE`, `RGB_LED_COUNT`, `RGB_LED_DATA_PIN`	Built-in RGB LED strip
`HAS_BATTERY_MONITOR`, `BATT_ADC_PIN`, `BATT_ADC_DIVIDER_TOP/BOTTOM`	Battery voltage ADC and resistor divider ratio
`HAS_CHARGER`, `CHG_EN_PIN`, `CHG_STAT_PIN`, `BATT_STAT_PIN`	Charger enable / status pins

SD card

SD_MODE selects the interface:

`SD_MODE`	Interface
`0`	SPI — use `SD_SLOT`, `SD_CS_PIN`, `SD_SCK_PIN`, `SD_MOSI_PIN`, `SD_MISO_PIN`
`2`	SDMMC — use `SD_SLOT`, `SD_WIDTH`, `SD_CLK_PIN`, `SD_CMD_PIN`, `SD_D0_PIN`..``SD_D3_PIN``

Mounting (SDMMC, SD_MODE == 2):

import machine, os, hub
b = hub.board
sd = machine.SDCard(slot=b.SD_SLOT, width=b.SD_WIDTH)
os.mount(sd, "/sd")

Mounting (SPI, SD_MODE == 0):

import machine, os, hub
b = hub.board
sd = machine.SDCard(slot=b.SD_SLOT,
                    sck=b.SD_SCK_PIN, mosi=b.SD_MOSI_PIN,
                    miso=b.SD_MISO_PIN, cs=b.SD_CS_PIN)
os.mount(sd, "/sd")

The remaining SD exports: SD_D1_PIN..``SD_D3_PIN`` (wide-bus SDMMC), SD_CMD_PIN, SD_CLK_PIN (SDMMC clock). Pin values of -1 (machine.PIN_NONE) indicate lines not wired on this board variant.

Port pins

Each external LPF2 port has a UART bus, two ID pins and two PWM channels:

Attribute	Meaning
`HAS_PORT_x`	1 if port `x` is populated on this board
`PORT_x_UART_BUS`	Logical bus (native UART or UART bridge) for LPF2 protocol
`PORT_x_ID1_PIN` / `PORT_x_ID2_PIN`	Port identification lines (logical pins)
`PORT_x_PWM1_PIN` / `PORT_x_PWM2_PIN`	H-bridge PWM channels (logical pins)

Where x is A, B, C, D, E, or F. For normal motor/sensor use, drive ports via the LPF2 API (Motors) rather than reading these pins directly.