Schematics

PE7/ADC9
1
AGND
2
PE0
3
VUSB
4
VDDIO
5
VBAT
6
DGND
7
VDDBT
8
PWRKEY
9
BT ANT
10
BT OSCI
11
BT OSCO
12
ADC5/PB3
13
ADC10/MICL/PF2
14
DACR
15
DACL
16
U1
1
2
BT-ANT1
ANTENNA_PIFA
GND
L1
NC
R1 0R
BT RF
BT-OSCI
BT-OSCO
Y1
26MHZ
GNDDACL
GND
VDDIO
VDDBT
MUTE
GND
C5 105
C4 105
C3 104
GND
VBUS
1
D-
2
D+
3
GND
4
G
5
G
6
G
7
G
8
G
9
USB1
USB-MICRO
VUSB
BT1
3.4V~4.2V
C10
105
VBAT
R2
3K6
CHRG
1
GND
2
BAT
3
VCC
4
PROG
5
U2
4054
CHARGE
R3
1K
LED00
LED1
0603/
GND
S1
VMCU
VMCU
LOUL-
LOUL+
C8
683
R4 33K
GND
C7 105
MUTE
C12
106
GND
DACL
VMCU
C9 103
1
2
J1 SPK
R5
15K
GND
SD
1
BYP
2
MODE
3
IN
4
VON
5
VDD
6
GND
7
VOP
8
GND
9
U3
5128
LOUL+
LOUL-
LED 2
LED3
VMCU
1
23
Q1
9014
GND
R7
10K
LED 2
R8
100K
VMCU
LED 1
LED2
0603/
GND
LED 1
C6
106
R13
0R
R12
100K
VMCU
R11
0R
VMCU
R10
1R5
C11 105
GND
R9
0R
AB-5337