Figure 2-37. Data Flow Diagram - Epson C11C605001 - DFX 9000 B/W Dot-matrix Printer Service Manual

Service Manual
EPL-9000
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 SelecType setting "PAGE
PROTECT".
The E05A91 transmits image data stored in the V-RAM to E05A92. The E05A92 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 capaaty equivalent to several lines. This is controlled by the E05A92,
which synchronizes and transmits the temporary buffer's data to the engine controller board. The
CPU
(ICI)
Development
I -
Buffer ;
Input
Rev. A
'RAM System Area
DRAM

Figure 2-37. Data Flow Diagram

Operating Principles
Host Computer
2-25