Epson Stylus Photo785EPX, Service Manual

Page: 49 / 192

EPSON Stylus PHOTO 895/785EPX/915/825 Revision B
Operating Principles Electrical Circuit Operating Principles 49
Following shows you the major characteristic of this main board.
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Use of the newly designed board C408/C498 MAIN
This product uses the newly developed C408/C498 MAIN board with the
PCMCIA card slot, preview monitor (option) and monochrome panel (LCD)
added. This board is divided into the printer and Printon sections. The same
control as the conventional models is operated in the printer section, and the
control for the PCMCIA slot, monochrome panel and printer PNL is operated in
the Printon section.
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Applicable to the ECP mode
The parallel IF, which connects the printer and Printon sections, can receive the
high speed data by means of the DMA function up to at the maximum
500 kbytes/second. The product can also receive the data transmitted at the
maximum 800 kbytes/second (ECP mode) in compliance with the IEEE1284 since
it is applicable to the ECP mode.
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Applicable to the USB (Universal Serial Bus) Rev.1.1IF (Full speed/12 Mbps.
without a hub)
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Motor current control by D/A of CPU and ladder circuit of resistors
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Use of united IC of the reset circuit and EEPROM for the simple system design.
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Low power consumption is realized by designing logic circuit on the 3.3V power
supply. The following table shows the chips that operate by 3.3V and +5V.
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Use of the HJFK image processing
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SDRAM is mounted.
Table 2-8. 3.3V & 5V Drive Chips
+3.3V +5V
• CPU
• P-ROM
• D-RAM
• SD-RAM
• Sensors
• I/F Circuit
• PNL Board