Module model: BTM321
Bluetooth chip: QCC3021, 32m SPI flash built in the module
Bluetooth version: 5.1
Module size: 13mm x 18mm x 2.5mm
Power supply voltage: 3.0-4.3V
Bluetooth module specification:
http://www.tianjiarun.com/zb_users/upload/2020/04/SJR-BTM321_SPEC.pdf
Default firmware:
1. Support SBC, AAC decoding, No call function,Optional I2S, analog output
2. Key Description:
SYS_ CTRL: power on at high level, power off at low level, and enter pairing mode automatically when starting
PIO2: short press play pause, long press 3 seconds to enter pairing, long press 5 seconds to clear pairing record
PIO3: short press the previous song, long press to decrease volume
PIO4: short press one song, long press to increase volume
PIO5: connect high level, not connect low level
PIO19: with audio output high level, without audio low level
PIO20: output for SPDIF
3. Description of codec indicator:
Bluetooth not connected: LED0 LED1 Alternate flicker
Bluetooth connected: LED1 is always on
Bluetooth audio playback: LED1 is always on