1. Introduction
14
The serial ports are configured as DTE and are available through the J1 80-pin
frontplane connector. Optional cables convert the serial port interface to standard 9-pin
D-shell connectors. The ZT 90200 cable provides the serial interface for the ZT 8904
and ZT 89CT04. The ZT 90203 cable provides the serial interface for the ZT 8903. A
null-modem option is required to convert the DTE configuration to DCE.
See Chapter 8, "
Serial Controller
" for more information.
IEEE 1284 Parallel Port
The ZT 8904 includes an IEEE 1284 parallel port for supporting Centronics, EPP, and
ECP devices. The parallel port interface is available through the J1 80-pin frontplane
connector. An optional cable converts the parallel port interface to a standard 25-pin D-
shell connector. The ZT 90200 cable provides the parallel interface for the ZT 8904 and
ZT 89CT04. The ZT 90203 cable provides the parallel interface for the ZT 8903.
See Chapter 9, "
Centronics Printer Interface
" for more information.
Parallel I/O
The ZT 8904 includes three 8-bit parallel I/O ports for a total of 24 parallel I/O lines.
Each line is programmable as an input or an output with readback. The outputs sink
12 mA and do not glitch during power cycles. The 24 lines, available through the J4 50-
pin frontplane connector, also support software programmable signal debounce and
event sense interrupt generation.
An optional cable (ZT 90072 Digital I/O Cable) connects the parallel I/O interface to an
8, 16, or 24 position I/O module mounting rack, such as Ziatech's ZT 2226 24-Channel
I/O Mounting Rack or those offered by Opto 22
®
.
See Chapter 10, "
Parallel I/O
" for more information.
Interrupts
Two interrupt controllers provide a total of 15 interrupt inputs. Interrupt controller
features include support for level-triggered and edge-triggered inputs, fixed and rotating
priorities, and individual input masking. Interrupt sources include counter/timers, serial
I/O, parallel I/O, real-time clock, keyboard, printer, optional IDE drive, and multiple
master communications. There are also three frontplane and four STD bus interrupt
sources. Frontplane interrupts are available via connector J2.
See Chapter 4, "
Interrupt Controller
" for more information.