Samsung SCX-1100 Service Manual page 82

3-5-2-3 Host Interface Section
(HI : Jupiter3 interface section)
Unlike the existing DuoIP sequence, OA-980 exchanges
Command and data with Jupiter 3 in the Multiplexed 8bit
Bus(data & address) mode. Namely, it does not receive
Address and Data simultaneously, but receive data after
receiving Address first using Data Bus of Jupiter3.
HI Section also supports the data movement in the DMA
mode. Accordingly, when transmitting large capacity of
Image data(RGB data of MultiMedCard), it uses the DMA
mode.
Samsung Electronics
1. Multiplexed 8bit Bus(data & address) mode
nce Jupiter3 may not support Multiplexed 8bit Bus(data &
address) mode used by OA-980, it configured a circuit addi-
tionally so that mutual Interface may be possible by making
required signal using two NOR GATE(UR16) and one OR
Gate(U40).
As REG_ADDR_VAL(pin27) signal is the signal for OA-980
to play a role of informing that value input into 8bit of OA-
980 Bus is not Data but Address value, when ADDR(10) is
"High" and /IP_CS, /WR "Low," "High" shall be generated as
shown in the circuit diagram. See figure (16). At this time,
since /WR_L(pin31), the Write signal of OA-980, should be
maintained in "High," the signal shall be generated in case
actual Write is accomplished with one OR Gate(U18),
namely,
REG_ADDR_VAL (pin27) is "High," input the Address value
of OA-980, and when "Low, from the standpoint of Jupiter3,
it may Read or Write One Byte Data using two Cycles by
Reading or Writing relevant Data of (to) Address.
<Figure 16. Hi Block Timing diagram(1)>
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CIRCUIT DESCRIPTION
only when ADDR(10) is
Repair Manual
"Low," When
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