Epson EPL-9000, Service Manual

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EPL-9000
Service Manual Operating Principles
Print data and commands transmitted from the host computer via parallel, serial, or optional
interfaces are read using the interrupt process of the CPU and stored in the DRAM input buffer.
Data and commands in the input buffer are processed by the CPU, which then stores the printing
bitmap data (image data) in the V (video) -RAM (image buffer) in the DRAM. The size of the
V-RAM depends on the available DRAM size. A “PRINT OVERRUN” occurs when the V-RAM is
so small that the CPU cannot process data faster than it is transmitted to the engine controller
board. If such an error occurs, the user can increase the V-RAM by using
setting “PAGE
PROTECT”.
The transmits image data stored in the V-RAM to The changes image the
data format from 32 bits parallel data to serial data, and stores it in the internal temporary buffer.
The temporary buffer has a
equivalent to several lines. This is controlled by the
which synchronizes and transmits the temporary buffer’s data to the engine controller board. The
then manipulates the printer data according to the BiRITech and EMGTech settings.
CPU
(ICI)
Development
I -
Host Computer
I n p u t
B u f f e r
‘RAM System Area
DRAM
Figure 2-37. Data Flow Diagram
Rev.
2-25