Table of Contents
Advertisement
Microprocessor
The microprocessor (an IBM PowerPC) is the central processor
unit which supervises system functions, executes the printer
firmware, manipulates data, and controls input/output data busses.
It has two built-in serial ports, a two channel DMA (Direct Memory
Access) controller, a timer module, clock generator, and an on-
board chip select generator. One serial port connects to the Mini-
DIN connector which can be used to communicate with the host
computer; the other serial port interfaces to the Control Panel.
One DMA channel supplies data to the gate array for jet firing; the
other DMA channel is used to receive data through the parallel
port via the gate array, or the serial port when using a high speed
serial mode. One timer generates a servo interrupt every millisec-
ond; the other is used for timing the Stepper Motor.
A divide-by-two circuit generates the 33MHz system clock from a
66MHz crystal reference (X1).
The chip select generator is programmed to generate chip selects at
the appropriate addresses, with the appropriate data size (byte,
word) and with the appropriate number of wait states.
Gate Array
Figure 2-6. Gate Array.
Novajet PROe Series Service Manual
Theory of Operation
31
Advertisement
Table of Contents
