jielie

HW-770 V0.2

Just an bluetooth audio board like the XY-BT-MINI, etc.

hw-770 and hw-221

front side back side with the JL chip removed

Some details

On the board the pins are utilized as follows:

Pin Usage Note
PB5 Onboard LED  
PC5 Mute Driven high when no sound is playing
USBDM/PC3 USB D- Exposed on a pad on back side (next to VCC)
USBDP USB D+ Exposed on a pad on back side (next to GND)

Extra functions that are available in the firmware my board shipped with:

Pin Usage Note
PA0/PA2 Mic bias  
PA1 (MIC) Microphone  
PA3 Line in L  
PA4 Line in R  
PB4 ?  
PB6 Line in sense Active low
PB7 ?  
PC4 ADKEY Pulled up by an external 22k resistor on board

ADkeys are as follows:

Resistance Key < long press
0R Prev Vol-
3k Play/Pause Mode
6k2 Next Vol+
9k1 Mode  
24k Repeat  
33k EQ  
51k Vol+ Vol+
100k Vol- Vol-