Xerox WorkCentre 385, Руководство по обслуживанию

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WorkCentre 385
Circuit Description
12/98
7 - 28
Power Monitor (U35: KIA7045AP)
If 5V power to KIA7045F drops to b4.65V
and +4.35V (typically 4.5V), power failure will be
indicated and the output of KIA7045F will go “low”.
This cause the flash memory (U27M28) and
KS32C6100 (U1) to became active (“low”=reset).
The flash memory and KS32C6100 reset causes
the SCAN-IP connected to /RST_OUT terminal,
modem, print controller to be reset. The output
terminal of KIA7045AP is an open
drain configuration, output through a 5.1K pull-up
resistor.
Watch Dog Output (/RSTO)
Watch dog timer is programmable counter in the
KS32C6100. As initial state is enable, set the state
to be disable. After system switches to initialize
mode, set the state to be enable. If the watch dog
reset and power on, according to default setting,
Memory
SUMMARY
System memory consists of 2MB flash memory,
32KB SRAM, 8MB DRAM. MASKROM is selected
optional.
MEMORY STRUCTURE
Flash memory and DRAM are selected by chip
select (/RCSO-1, /FMEM_CS, /RASO-1, /SCS, /
CASO-3) lines, and data is accessed by the units
position of the word.
Modem, TX & RX Related Circuits
MODEM
These circuits control signal transmission between
the internal modem and the LIU or a remote
modem. The KS16117 modem is a signal-chip fax-
modem having features to detect and generate
DTMF tones. TX OUT (pin44) is the modem output
port, and RXIN (pin45) is the input port. /PORI
(pin67) from KS32C6100 is the signal which
enables modem initialization at system power on.
D0~D7 (pin8-15) are the data bus RS0-RS4
(pin56~60) are internal resister select signals
which determine the mode.
/CS (pin54) is chip select, /RD (pin55), /WR
(pin53) are read and write control signals. /IRQ
(pin52) is modem interrupt output signal. The
transmission speed of KS16117 is maximum 14.4
Kbps.
TRANSMIT CIRCUIT
This circuit controls transmission of analog signals
from the modem (KS16117).
Output voltage from the modem (TXOUT:44) is
buffered through LIU PBA and OP-AMP after
signal smoothing and filtering, and finally output to
the line.
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