User`s manual

Am186
TM
CC Microcontroller ISDN TA Reference Design Manual
2-10
Serial PC Interface
The serial port may be used for communication with a PC. The Sipex high-speed
RS-232 transceiver is used to provide serial data rates up to 230 kbps. The DCE
serial connection is made through a standard female DB-9, which uses a straight-
through serial cable. PIO1 and PIO28 are used to provide extra flow control
signaling to support Plug and Play (PnP) operation. The two LEDs are used to
indicate transmit and receive activity. The schematic for the serial interface is
shown in Figure 2-7.
Figure 2-7. ISDN TA High Speed Serial Interface
VCC5
CR2
LED RT GREEN
1 2
U13
SP211
2
3
45
6
7
8 9
10
11
12
13
14
15
16
17
19
20
21
22 23
24
25
26 27
1
28
18
T1OUT
T2OUT
R2INR2OUT
T2IN
T1IN
R1OUT R1IN
GND
VCC
C1+
V+
C1-
C2+
C2-
V-
R5OUT
T3IN
T4IN
R4OUT R4IN
EN#
SD
R3OUT R3IN
T3OUT
T4OUT
R5IN
P2
CONNECTOR DB9
5
9
4
8
3
7
2
6
1
10
11
CR3
LED RT GREEN
1 2
C47
1000pF
C46
1000pF
C45
1000pF
C44
1000pF
C48
1000pF
C49
1000pF
C42
0.1uF
C50
0.1uF
C43
0.1uF
C51
0.1uF
R25
680
R26
680
R101 100
R102 100
R103 100
R104 100
R105 100
R106 100
PIO1
RTRHU#
RXDHU
CTSHU#
TXDHU
PIO28
about.book Page 10 Friday, December 18, 1998 9:41 AM