Measurement Computing Digital232 - Manual (Page 5)

Section 1 Introduction
1.1
Introduction
1.1 General Description
The Digital232 is a digital input and output interface to the RS-232 standard. The
unit has 40 TTL level digital I/O lines, divided into five 8-bit ports. Each port is
software programmable as input or output.
The Digital232 has several features which give it versatile interface capability. A
trigger output signal can be asserted on a Trigger command. Edge-triggered inputs
can generate a Service Request to the RS-232 host. Five data formats are software
programmable, including hexadecimal, ASCII, binary, high speed binary and decimal.
There are also individual bit set and bit clear commands.
A status mode enables the host to interrogate the programmed status of the
Digital232 at any time. A self-test is initiated at power-on which checks for proper
RAM and ROM operation.
When data is requested, the Digital232 will output from all forty bits, all input
ports, all output ports, or from a specific 8 bit port. When being programmed, the unit
will input data and programming information from the host, and output the data to the
selected I/O port.