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2.2.1.5
Figure 2-36 shows the parallel interface circuit block diagram. Data sent from the host computer is
latched within the E05B01 by the STROBE signaL
automatically to stop the host computer from sending additional data. The CPU resets the BUSY
signal after reading the data from the E05B01, so that the printer is ready to receive more data from
the host computer.
DATA
STROBE
BUSY
2.2.1.6 Optional Ty~B Interface
This printer supports an Epson Type-B optional interface, which is controlled by the INH and BIF
from
Video Interface
2.2.1.7
transmits data from the V-RAM (in the system RAM) to the SRAM using ASIC EQ5A83. The ASIC
converts the image data in the SRAM from parallel to serial, synchronizes it, and then transmits it
to the engine controller circuit. In other words, the SRAM is a temporary buffer used to transmit
the image data to the engine controller arcuit. This serial image data is the VIDEO signal of the
video interface.
The signal line of the internal video interface circuit can be divided into four groups. The first
group (PRINT, CPRDY, EPRDY, and PRDY) gives the status of either the video or engine controller
and indicates whether they are ready to communicate with each other or ready to start printing.
The second group (VSYNC) is the synchronizing signal for printing. The third group (VIDEO) is
the serial video data signal. The fourth group (CMD, SRCLK, CTBSY, and ETBSY) is used to
transfer the commands (from the video controller) or the status (from the engine controller) for
printer mechanism control.
This printer has a standard RITech function. This function modifies the VIDEO signal with ASIC
2-24
. . . . . . ,
. . . . . .
Figure 2-36.
Parallel Interface Circuit
-
-
-
The E05B01 outputs the BUSY signal
Latch
Rev. A
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