Epson FX-870/1170 - Manual (Page 139)

Principles of Operation
Table 6-5 lists the of the main of the CO94 MAIN.
F Receives data from the host computer and 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
the printhead drive circuit. Also controls various printer mechanism
parts, such as the motors.
(IC4)
PROM (iC3)
RAM (iC2)
This gate array mainly performs the following five functions:
l
Memory management
l
Centronics control
l
Control panel control
l
control
l
Printhead drive circuit control
The PROM contains the program that runs the CPU.
The RAM contains the CPU working area and the buffers.
The is used to store information such as the top-of-form
position.
Drive circuit for PF motor
(iC5) Drive circuit for CR motor
6-24
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