The **HM-10** is a popular Bluetooth Low Energy (BLE) 4.0 module based on the **Texas Instruments CC2540 or CC2541** System-on-Chip (SoC). It is widely used in DIY electronics for communication between microcontrollers (like Arduino) and smartphones. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Bluetooth Version** | Bluetooth 4.0 BLE | | **Chipset** | TI CC2540 / CC2541 | | **Operating Voltage** | 3.3V to 6V (usually via 5V adapter board) | | **Logic Level** | 3.3V (Requires level shifting for 5V systems) | | **Working Current** | 0.5mA (Sleep) to 8.5mA (Active) | | **Frequency** | 2.4GHz ISM band | | **Communication Protocol** | UART (Serial) | --- ### 2. Major Electronic Components The HM-10 usually comes in two forms: the bare **SMD module** or the **HC-05 compatible breakout board**. #### A. The SoC (CC2541/CC2540) The heart of the module. It contains the 8051 microcontroller core, the Bluetooth radio, and the flash memory where the firmware resides. #### B. Crystal Oscillators * **32MHz Crystal:** Provides the high-speed clock for the RF transceiver and CPU. * **32.768kHz Crystal:** Used for low-power sleep modes and timing. #### C. Power Management (Breakout Board) * **LDO Voltage Regulator:** Usually a small 3.3V regulator (like the XC6206) that allows the module to be powered by 5V. * **Filtering Capacitors:** Used to stabilize the power supply and reduce noise. #### D. Antenna * **PCB Trace Antenna:** Most HM-10 modules feature an integrated meandered inverted-F antenna (MIFA) etched directly onto the circuit board. --- ### 3. Pinout Configuration The breakout board version typically features 6 pins: 1. **VCC:** Power supply (3.6V - 6V). 2. **GND:** Common ground. 3. **TXD:** Transmit Data (Serial Output - 3.3V Level). 4. **RXD:** Receive Data (Serial Input - 3.3V Level). 5. **STATE:** Indicates if the device is connected (High/Low). 6. **BRK/EN:** Used to interrupt the connection or reset the module. --- ### 4. Comparison: Genuine vs. Clone It is important to note that many "HM-10" modules on the market are actually **CC2541 Clones** (like the MLT-BT05 or CC41-A). * **Genuine HM-10:** Supports the full AT command set from JNHuaMao and can be firmware updated. * **Clones:** Often have a limited AT command set and may behave differently during pairing. ---