User's Manual

UC864-G Hardware User Guide

DRAFT

- 29/10/07

The signals of the UC864-G serial port are:

RS232

Number

Signal

UC864-G

Pad

Number

Name Usage

1 DCD -

dcd_uart

32 Data Carrier Detect Output from the UC864-G that indicates

the carrier presence

2 RXD -

tx_uart

26 Transmit line *see Note Output transmit line of UC864-G UART

3 TXD -

rx_uart

25 Receive line *see Note Input receive of the UC864-G UART

4 DTR -

dtr_uart

29 Data Terminal Ready Input to the UC864-G that controls the

DTE READY condition

5 GND 5,6,7 Ground ground

6 DSR -

dsr_uart

27 Data Set Ready Output from the UC864-G that indicates

the module is ready

7 RTS -

rts_uart

31 Request to Send Input to the UC864-G that controls the

Hardware flow control

8 CTS -

cts_uart

28 Clear to Send Output from the UC864-G that controls

the Hardware flow control

9 RI - ri_uart 30 Ring Indicator Output from the UC864-G that indicates

the incoming call condition

NOTE: According to V.24, RX/TX signal names are referred to the application side, therefore on

the UC864-G side these signal are on the opposite direction: TXD on the application side will

be connected to the receive line (here named TXD/ rx_uart ) of the UC864-G serial port and

vice versa for RX.

TIP: For a minimum implementation, only the TXD and RXD lines can be connected, the other

lines can be left open provided a software flow control is implemented.