Product features
High-speed ARM9E core MCU
2.4G/1T1R
160k programming space, 20KB RAM
Power supply voltage 0.9-3.6v
Ultra low supply voltage, low power consumption
Built-in crystal, high stability
Small chip package 4x4
Rich peripheral interface, SPI, I2C, ADC, UART, PWM, GPIO
Widely used in the Internet of Things
High-speed 10-bit multi-channel ADC with internal filtering
Easy to connect, fast speed

Function description
The module function is mainly to realize the mutual conversion of serial data.
In this mode, the HLK-B20 module sends the received data from the serial port.
Serial port working state conversion

Figure: Serial port working state transition
The module defines the working state of the serial port as two modes: transparent transmission mode and AT command mode.
After normal power-on, the module directly enters the transparent mode. In any state, keeping the ES0 pin low for longer than Tes and less than Trst will immediately enter the AT command mode
Service declaration
Supports seven days of returns without reason
If the delivery is lost, return is supported
If the delivery is damaged, return is supported
Free exchange within 90 days
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