Integra CROMA24 - Manual (Page 30)

30 Theory of Operation
Croma24 Service Manual
Microprocessor
The microprocessor (a Motorola MC68322) is the central processor
unit which supervises system functions, executes the printer firm-
ware, manipulates data, and controls input/output data busses. It
has a built-in parallel port, a two channel DMA (Direct Memory
Access) controller, timer module, clock generator, and an on-board
chip select generator. One DMA channel supplies data to the gate
array for jet firing; the other DMA channel is used to receive data
through the serial port via the gate array, or the serial port when
using a high speed serial mode. One timer generates a servo inter-
rupt every millisecond.
The microprocessor halves the 40MHz crystal reference (X1) signal
to create the 20MHz system clock that is used for timing of all
internal circuitry.
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 2-5. Gate Array.