Schematics

D
C
B
A
1 2 3 4 5 6
A
B
C
D
654321
MICIN
VBAT
+5V
VDDIO
S1
NC
D2
RED
D1
BLUE
BAT+1
B+
BAT-1
B-
C1 NC
C2 105
Y1
26MHZ
5
VDDIO
6
VBAT
8
VDDBT
2
AGND
7
DGND
10
BT_ANT
11
BT_OSCI
12
BT_OSCO
1
PE7/ADC9
4
VUSB
15
VCMBUF
9
PWRKEY
14
ADC10/MICL/PF2
13
ADC5/PB3
3
PE0
16
DACL
U1
AB5377A2 - SOP16 150mil
P3
L+
P4
L-
+
MIC1
P3
P4
+5V
GND
2
2
3
3
1
1
R1
NC
R2
NC
1
KEY
2
GND
3
TH
6
NC
5
VBAT
4
VBAT
U2
6233D
C6
475
1
J2
C7
NC
VBAT
+5V
VDDIO
PWRKEY
DACL#
DACLPE7
+5V
VBAT
VDDIO
MICIN
PB3
PWRKEY
PE7
DACL#
DACL
PB3
VBAT
PWRKEY
BT_ANT