Synchronous Serial Ports - Motorola MVME1603 Installation And Use Manual

Introduction
C

Synchronous Serial Ports

C-2
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. The
EIA-232-D drivers and receivers that complete the asynchronous serial
interface are located on the MVME760 (for the MVME1600-001 base
board) or MVME712M (for the MVME1600-011 base board) transition
module.
The MVME1603/MVME1604 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 MVME1603/MVME1604
Single Board Computer Programmer's Reference Guide and to the vendor
documentation for the ISASIO device.
The MVME1603/MVME1604 uses a Zilog Z85230 ESCC (Enhanced
Serial Communications Controller) with a 10MHz clock to implement the
two synchronous/asynchronous serial communications ports, which for
the MVME1600-001 base board are routed through P2 and for the
MVME1600-011 base board are routed through the front panel as well as
P2. The Z85230 handles both synchronous (SDLC/HDLC) and
asynchronous protocols. The hardware supports asynchronous serial baud
rates of 110B/s to 38.4KB/s and synchronous baud rates of up to 2.5MB/s.
Each port supports the CTS, DCD, RTS, and DTR control signals, as well
as the TxD and RxD transmit/receive data signals and TxC/RxC
synchronous clock signals. Since not all modem control lines are available
in the Z85230, a Z8536 CIO device is used to provide the missing modem
lines.
In addition to complementing the Z85230 ESCC by supplying modem
control lines not present on the Z85230 ESCC, the Z8536 CIO device
provides a way to request the module ID of the synchronous/asynchronous
serial ports on the transition module. Refer to the Z8536 data sheet and to
the MVME1603/MVME1604 Single Board Computer Programmer's
Reference Guide for further information.