The 3P+S Input/Output S-100 board was
designed to meet all the I/O needs of most early 8800 system users. For
example, one teletype and two TV typewriters with keyboards could be operate
simultaneously with the 8800 through only one 3P+S. Similarly, one
RS-232-C modem, a teletype, and one TV typewriter plus another parallel data
device could all be interfaced with one 3P+S at the same time.
One parallel port was available to set
up control conditions for both parallel and serial ports, as well as to set the
serial I/O baud rate under program control. The baud rate could be set
from 35 to 9600 Baud. Another parallel port allowed polling the input data
available flags and external device ready flags. This port also permitted
checking the serial I/O error flags. Full handshaking with both input and
output peripherals could be implemented.
Module addressing was jumper selectable
to any one of 64 I/O ports within the 8800 range of 256 I/O ports.
Additional flexibility allowed either the UART (Universal Asynchronous Receiver
Transmitter) and control port or the two parallel ports to occupy the lower two
relative addresses. Interfacing to the 8800 vectored interrupt bus was provided
as a jumper selectable option. Any of the UART error flags or handÂshaking
signals could be used to generate interrupts. A Vectored Interrupt Module,
however, was required for this purpose.
The manual for this board can be obtained
here.
Click
here to see an early review of the CUTS tape standard that appeared in
the March1976 issue of Popular Electronics.
