HC12 Data Transceiver Module 433 MHz – 100 Channels

Description

The HC-12 is a module consisting of the Si4438 transceiver and the STM8S003FS microcontroller.

The operating frequency of the Si4438 transceiver ranges from 433.4 to 473.0 MHz, with a channel step of 400 kHz, up to a maximum of 100 channels. The maximum transmission power is 20 dBm (100 mW), the reception sensitivity is -129 dBm, and it has two 64-byte Rx and Tx FIFO memories. Used with an external antenna, it can communicate up to 1 km outdoors.

The STM8S003FS is an 8-bit microcontroller with 8 kB of flash memory, 128 bytes of EEPROM, and a 10-bit ADC. It supports UART, SPI, and I²C communication and has various I/O pins. It offers many of the same features as its ATMega and XMC counterparts. It is programmed to control the Si4438 transceiver and to manage UART communication between the HC-12 and whatever is connected at the other end.

It features a 4-pin TTL-level UART interface (VCC, GND, TXD, RXD), with a 5th pin (SET) used to change the module configuration. The HC-12 has 100 supported channels spaced 400 kHz apart, eight transmission levels, eight supported baud rates, and three different operating modes. When the “SET” pin is set to a low logic level, it allows selecting various settings using AT commands sent to the “RXD” pin.

The default configuration of the HC-12 is FU3: on channel 1, FU3 is a fully automatic and transparent setting (for other devices) that adapts to the baud rate of the connected device.

Note: as the baud rate increases, the receiver sensitivity decreases. You can return to factory settings by sending “AT+DEFAULT” once.

Technical specifications

• Communication distance (default): 600 meters (communication distance is adjustable up to 1 km, over-the-air baud rate 5000 bps)

Documentation and useful links

• Datasheet