Principles of Operation

Table 6-5 lists the fimctiona of the main componente of the CO94 MAIN.

Table 6-5. Functions of Main Components of CO94 MAIN

IC or Circuit

 

Functions

 

 

 

 

 

 

 

TMP90C041

F (2Cl)

Receives data from the host computer and loads it to the input buffer in

 

 

 

 

RAM. Expands the input data held in the buffer to create image data.

 

 

 

 

Loads the image data to the image buffer in RAM. Transfers the image

 

 

 

 

datato the printhead drive circuit. Also controls various printer mechanism

 

 

 

 

parts, such as the motors.

 

 

 

 

 

 

E05A66YA (IC4)

This gate array mainly performs the following five functions:

 

 

 

 

Memory management

 

 

 

 

Centronics I/F control

 

 

 

 

Control panel control

 

 

 

 

E2PROM control

 

 

 

 

Printhead drive circuit control

 

 

 

 

 

 

PROM (iC3)

The PROM contains the program that runs the CPU.

 

 

 

 

 

 

 

RAM (iC2)

 

The RAM contains the CPU working area and the buffers.

-

 

 

 

 

E2PROM (XI)

The E*PROM is used to store information such as the top-of-form

 

 

 

 

position.

 

 

 

 

 

 

 

UPAl475H

(ICl)

Drive circuit for PF motor

 

 

 

 

 

 

 

SLA7024M

(iC5)

Drive circuit for CR motor

 

 

 

 

 

 

 

 

-

6-24

Epson FX-87W1170