S i 2 4 9 3 / 5 7 / 3 4 / 1 5 / 0 4
Rev. 0.6
21
Figure 17. Audio Amplifier Schematic
Figure 18. UART Mux Schematic
SPEAKER
AOUT
VCC
C21
820 pF
R3
47 k
R4
3 k
+
C24
100 uF
1
2
R5
10
C22
0.1 uF
C23
0.1 uF
C20
0.1 uF
+
-
U10
LM386M-1
3
2
5
6
1
4
8
7
TXD_T
RTS_T
DTR_T
TXD_U
RTS_U
DTR_U
O\E\
S
DSR_M
RXD_M
CD_M
RI_M
CTS_M
RXD_T
CTS_T
DSR_T
CD_T
RI_T
RXD_U
CTS_U
DSR_U
CD_U
RI_U
DTR_M
RTS_M
TXD_M
VCC
"CTS_T"
"RXD_T"
"RXD_U"
"CTS_U"
TP13
TP14
TP15
U8
74CBT3257/SO
1B1
2
2B1
5
3B1
11
4B1
14
1A
4
2A
7
3A
9
4A
12
1B2
3
2B2
6
3B2
10
4B2
13
OE
15
S
1
R19
10k
U7
74CBT3257/SO
1B1
2
2B1
5
3B1
11
4B1
14
1A
4
2A
7
3A
9
4A
12
1B2
3
2B2
6
3B2
10
4B2
13
OE
15
S
1
TP12
R18
10k
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