Hardware Description
ESP32 Introduction
HALMET is based on the powerful ESP32-WROOM-32E microcontroller module. The ESP32 is a dual-core microcontroller with built-in WiFi and Bluetooth connectivity. The ESP32 is a popular choice for IoT applications due to its low cost, good set of peripherals, and ease of use.
GPIO Reference
HALMET reserves a number of GPIO pins for the input peripherals. Available GPIO pins are broken out to the 2x10 pin GPIO header. The following table lists the GPIO pins and their functions.
| GPIO | Function | Notes |
|---|---|---|
| 0 | Boot button | Enter bootloader when pulled low |
| 1 | TXD0 | Transmit data to USB |
| 2 | LED | Onboard red LED |
| 3 | RXD0 | Receive data from USB |
| 4 | 1-Wire DQ | 1-Wire data line |
| 5 | - | Available on the GPIO header |
| 12 | - / TDI | Available on the GPIO header. Optionally: JTAG TDI |
| 13 | - / TCK | Available on the GPIO header. Optionally: JTAG TCK |
| 14 | - / TMS | Available on the GPIO header. Optionally: JTAG TMS |
| 15 | - / TDO | Available on the GPIO header. Optionally: JTAG TDO |
| 16 | - | Available on the GPIO header |
| 17 | - | Available on the GPIO header |
| 18 | CAN RX | Receive from NMEA 2000 |
| 19 | CAN TX | Transmit to NMEA 2000 |
| 21 | I2C SDA | I2C data line. Used for analog input |
| 22 | I2C SCL | I2C clock line. Used for analog inputs |
| 23 | DI1 | Digital Input 1 |
| 25 | DI2 | Digital Input 2 |
| 27 | DI3 | Digital Input 3 |
| 26 | DI4 | Digital Input 4 |
| 32 | - | Available on the GPIO header |
| 33 | - | Available on the GPIO header |
| 34 | - | Available on the GPIO header |
| 35 | - | Available on the GPIO header |
| 36 (VP) | Input only | Available on the GPIO header |
| 39 (VN) | Input only | Available on the GPIO header |
Tour Around the Board
TODO
Connectors
TODO
Power Supply
TODO
NMEA 2000
TODO
Status LEDs
TODO
1-Wire
TODO
I2C
TODO
Last modified 2024-01-06: Initial HALMET docs (69661a1)