M66-IOT Board
Feature List #
Basic Overview #
The M66-IoT board is an optimized and feature-rich development board, making it an excellent choice for getting started with the Quectel M66 module. It is designed to simplify IoT prototyping and supports a wide range of applications, including solar-powered solutions through its integrated MPPT solar charging circuit.
Key highlights of the board include:
- Built-in Bluetooth antenna
- USB-to-Serial converter with Micro-USB port for easy debugging and programming
- Battery socket and charging circuit for Li-Po batteries, with charge status LED indicator
- MPPT-based solar charger, enabling efficient energy harvesting for off-grid deployments
In addition, the board integrates several useful sensors:
- Temperature and humidity sensor
- Ambient light sensor
- 3-axis accelerometer
Other features that enhance its versatility:
- 64 Mbit (8MB) flash memory (W25Q64)
- Microphone and speaker outputs
- External watchdog timer
- OLED interface support
- Level shifters on all I/O pins
With this comprehensive set of features, the M66-IoT board provides a powerful, all-in-one platform that goes far beyond typical development boards—ideal for building and testing next-generation IoT solutions.
M66-iot Board Resources #
Function Description #
The main component and interface placement of the evaluation board is shown in the following figure:
M66-IOT Board Configuration #
The detailed assignment of the peripheral interfaces on the evaluation board is as follows:
| NO. | Name | Comment |
|---|---|---|
| 1 | USB Type-C Connector | The USB port, connected to a CH343P USB-to-Serial converter, is used for programming and communication with the PC. |
| 2 | Reset Button | Pressing this button will reset the power supply of the entire board. |
| 3 | BLE Antenna | — |
| 4 | Battery Switch | You can use this switch to connect or disconnect the battery. |
| 5 | Li-Po Charger | Charger circuit for Li-Po battery, suitable for a 200 mAh battery; this LED indicates the charging status. |
| 6 | GSM Antenna | You can use a 2G antenna with a 50 Ω impedance, connected via a UFL connector. |
| 7 | 6-axis accelerometer sensor | Interfaced with the M66 module via I²C and includes a dedicated interrupt (INT) pin for event-driven operation. |
| 8 | SHT40 | The temperature and humidity sensor interfaces with the M66 module using the I²C communication protocol. |
| 9 | LEDs | Two LEDs: one for network status (Net Light) and one user LED (connected to the RTS pin). |
| 10 | Main UART M66 Selector | This switch allows toggling the main UART between the GPIO pins and the USB interface. |
| 11 | Watchdog Disable Circuit | External watchdog implemented using the TPS3823 chip. Note: if the WDG reset jumper is removed, you must reset the watchdog through the RTS pin. |
| 12 | Light Ambient Sensor | Ambient light sensor implemented using the BH1750 chip. |
| 13 | OLED Connector | Dedicated connector for connecting an OLED display via the I²C interface. |
| 14 | Solar MPPT Circuit | High-efficiency solar charging circuit with MPPT technology for optimal energy harvesting. |
| 15 | User Key Button | — |
| 16 | SIM1/SIM2 or SD Card Socket | Use either two SIM cards, or one SIM card and one microSD card. |
| 17 | Microphone and Speaker Output | Standard AUX output is supported. |
| 18 | 8 MB SPI Flash | 8 MB flash memory using the W25Q64 chip. |
| 19 | External Battery Socket | — |
| 20 | Level Shifter | — |
| 21 | USB to Serial Converter | — |
Evaluation board dimensions #
The main pin placement of the evaluation board is shown in the following figure:
tip #
- To program the board, slide the switch to the “UART ON USB” position and connect the USB cable to begin programming.
- The SPI interface pins are shared with the onboard flash memory. It is recommended not to use these pins to avoid conflicts.
- The battery switch simply connects or disconnects the battery from the circuit; it does not control charging or power regulation.
M66-IOT Board Interfaces #
| NO. | Name | Silkscreen | Comment |
|---|---|---|---|
| 1 | +5V | +5V | — |
| 2 | +3.3V | +3.3V | — |
| 3 | VDD_EXT | +VEXT | — |
| 4 | PCM_SYNC | MISO | Use only for SPI communication, and make sure to use a dedicated CS (Chip Select) pin. |
| 5 | PCM_IN | SCK | Use only for SPI communication, and make sure to use a dedicated CS (Chip Select) pin. |
| 6 | PCM_OUT | MOSI | Use only for SPI communication, and make sure to use a dedicated CS (Chip Select) pin. |
| 7 | PCM_CLK | CE | — |
| 8 | Auxiliary TXD | A-TXD | — |
| 9 | ADC | ADC | — |
| 10 | Auxiliary RXD | A-RXD | — |
| 11 | PWR KEY | PWR | — |
| 12 | GND | GND | — |
| 13 | +3.3V | +3.3V | — |
| 14 | Main TXD | M-TXD | Set the UART selection switch to “UART ON GPIO” to make the UART pins accessible. |
| 15 | Main RXD | M-RXD | Set the UART selection switch to “UART ON GPIO” to make the UART pins accessible. |
| 16 | Debug TXD | D-TXD | — |
| 17 | Debug RXD | D-RXD | — |
| 18 | RFTXMON | RFTX | — |
| 19 | RI | SCL | — |
| 20 | DCD | SDA | — |
Resource Download #
Updated on November 5, 2025