Introduction; Asynchronous Serial Ports; Synchronous Serial Ports - Motorola MVME2700 Series Installation And Use Manual

Introduction

As described in previous chapters of this manual, the MVME2700 serial
communications interface has four ports. Two of them are combined
synchronous/asynchronous ports; the other two are asynchronous only.
Both synchronous and asynchronous ports supply an EIA-232-D
DCE/DTE interface via P2 and the MVME712M transition module.

Asynchronous Serial Ports

The MVME2700 uses a PC87308 ISASIO chip from National
Semiconductor to implement the two asynchronous serial ports (in
addition to the disk drive controller, parallel I/O, and keyboard/mouse
interface).
The asynchronous ports provided by the ISASIO device are routed through
P2 and the associated transition module. The TTL-level signals from the
ISASIO chip are buffered through TTL drivers and series resistors, then
routed through EIA-232-D drivers and receivers to complete the
asynchronous serial interface enroute to the MVME712M transition
module.
The MVME2700 hardware supports asynchronous serial baud rates of
110B/s to 38.4Kb/s. For detailed programming information, refer to the
PCI and ISA bus discussions in the MVME2600/2700 Series Single Board
Computer Programmer's Reference Guide and to the vendor
documentation for the ISASIO device (listed in
Documentation.

Synchronous Serial Ports

The MVME2700 uses a Zilog Z85230 ESCC (Enhanced Serial
Communications Controller) with a 10 MHz clock to implement the two
synchronous/asynchronous serial communications ports, which are routed
BSerial Interconnections
B
Appendix D, Related
B-1