Functional Description - PEP Modular Computers Modular Computers RS485 User Manual

Chapter 6 Communications Modules
SMART I/O User's Manual

6.1.5 Functional Description

Figure 4.3.5.1: SM-RS232 Schematic Diagram
TxD
RxD
LED System
DTR
Driver Interface
CTS
GND
The serial interface is realized using the TxD3 and RxD3 lines of the 68302
SCC3 port on the SMART-BASE and for this reason this module can only
be used in the first slot on the SMART-BASE. Additionally, a software
programmed DTR function can be created with the CTS line being con-
nected to the interrupt line that is routed to the I/O controller of the SMART-
BASE. Although it is beyond the scope of this manual to discuss this con-
nection, PEP Modular Computers can provide advice on its implementation
6
if required.
The two LEDs on the front-panel indicate the status of the RxD and TxD
lines (ON means that the line is low).
An on-board serial EEPROM currently contains the ID-Byte for module
recognition and should not be altered. In the future, other module specific
data may be stored to provide more flexibility.
March 12, 1996 ©1996 PEP Modular Computers GmbH Page 6 - 7