Epson EPL-N1200, Service Manual

Page: 78 / 149

Print data and commands transmitted from the host computer via parallel-B/C, serial/LocalTalk, 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 bit
map data (image data) in the V (video) -RAM (image buffer) of 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 E05B17. The E05B17 changes the
image data format from 32 bits parallel data to serial data, and stores it in the internal temporary
buffer. The temporary buffer has a capacity equivalent to several lines. This is controlled by the
E05B17, which synchronizes and transmits the temporary buffer’s data to the engine controller
board. The E05B17 then manipulates the printer data according to the BiRITech setting.
Input Buffer
Development
VRAM System Area
Parallel/Serial
Converter
RITech
CPU
MB86930
(IC15)
E05A91
(IC1)
E05A93
(IC11)
E05B17
(IC16)
Video
or E05B27
(IC43)
DRAM
Buffer
SRAM
(IC17)
Host Computer
Figure 2-28. Data Flow Diagram
EPL-N1200 Service Manual Operating Principles
Rev. A 2-19