Integra CROMA24 service manual Microprocessor, Gate Array

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.

30 Theory of Operation