Tandy 1000
Technical Reference Manual
INTRODUCTION TO RS-232 ASYNCHRONOUS
COMMUNICATION BOARD
The RS-232 board
is
a single-channel asynchronous serial communications
board. The heart of the board
is
the WD8250 Asynchronous Communications
Element
(ACE),
that functions
as
a serial data input/output interface.
It
performs
serial-to-parallel conversion on data characters received from a peripheral
device or a modem, and parallel-to-serial conversion on data characters
re-
ceived from the CPU. Status information reported includes the type and con-
dition of the transfer operations performed by the ACE
as
well
as
any error
conditions.
The
WD8250 includes a programmable baud rate generator that
allows operation from 50
to
9600 baud. The WD8250 can be software tailored
to the user's requirements.
It
will
add and remove start bits, stop
bits,
and parity
bits.
It
supports
5-,
6-,
7-,
or
8-
bit characters with
1,
1
1
12,
or
2 stop bits.
Diagnostic capabilities provide loopback functions of transmit/receive and
in-
put/output signals. Other features include:
•
Full
double buffering which eliminates the need for precise
synchronization.
• Independent receiver clock input.
• False start bit detection.
• Line break generation and detection.
• Modem control functions: Clear To Send
(CTS),
Request
To
Send
(RTS),
Data
Set
Ready
(DRS),
Data Terminal Ready
(DTR),
Ring
Indicator
(RI),
and Carrier Detect (CD).
77
To Next Page
Loading...
Need help?
General
