Caple CM109 User Manual download pdf (Page 43)

BDM-610000082 Rev A Chapter 3: Connecting the cpuModule 35

Serial Port 1 (CN7) and Serial Port 2 (CN8)

Serial Port 1 (COM1) is implemented on connector CN7, and Serial Port 2 (COM2) is implemented on connector

CN8. The serial ports are normally configured as PC compatible full-duplex RS-232 ports, but you may use the

BIOS Setup program to reconfigure these ports as half-duplex RS-422 or full-duplex RS-422 or RS-485. If you

reconfigure the ports, you must also select the I/O address and corresponding interrupt using Setup. Table 13

provides the standard I/O addresses and corresponding interrupts.

Serial Port UART

The serial ports are implemented with a 16550/16750-compatible UART (Universal Asynchronous Receiver/

Transmitter). This UART is capable of baud rates up to 115.2 kbaud, and includes a 64-byte FIFO. Refer to any

standard PC-AT hardware reference for the register map of the UART.

RS-232 Serial Port (Default)

The default serial port mode is full-duplex RS-232. With this mode enabled, the serial port connectors must be

connected to RS-232 compatible devices. Table 14 provides the serial port connector pinout and shows how to

connect to an external DB-25 or DB-9 compatible serial connector.

Table 13 S erial Port Setting s

I/O Address (hex) IRQ

03F8 IRQ4

02F8 IRQ3

03E8 IRQ4

02E8 IRQ3

Table 14 Serial Port in RS-232 Mode

Pin Signal Function In/Out DB-25 DB-9

1 DCD Data Carrier Detect in 8 1

2DSRData Set Ready in66

3 RXD Receive Data in 3 2

4RTSRequest To Send out47

5TXDTransmit Data out23

6CTSClear To Send in58

7 DTR Data Terminal Ready out 20 4

8 RI Ring Indicate in 22 9

9,10 GND Signal Ground — 7 5

1 2 ... 38 39 40 41 42 43 44 45 46 47 48 ... 101 102

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Caple CM109 User Manual Page 43