Fujitsu M3097DG, Руководство OEM

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Appendix A-6
A.2.2 Bus signals
Signal name Type of signal
Initiator
Target
Data
DB0
DB1
DB2
DB3
DB4
DB5
DB6
DB7
(Data Bus n)
DBP
(Data Bus
Parity)
Eight data-bit signals, plus a parity-bit signal that
form a DATA BUS. DB(7) is the most significant
bit and has the highest priority during the
ARBITRATION phase. Bit number, significance,
and priority decrease downward to DB(0).
A data bit is defined as one when the signal value is
true. A data bit is defined as zero when the signal
value is false. Data parity DB(P) shall be odd.
Parity is undefined during the ARBITRATION
phase.
Control
signals
BSY
(Busy)
An “ORtied” signal that indicates that the bus is
being used
SEL
(Select)
An “ORtied” signal used either by an initiator to
select a target or by a target to reselect an initiator
RST
(Reset)
An “ORtied” signal that indicates the RESET
condition
C/ D
(Control/Data)
I/ O
(Input/Output)
MSG
The C/D, I/O, and MSG signals are used to
distinguish between the different information
transfer phases.
REQ
(Request)
During an information transfer phase, the target uses
this signal to request the initiator to transfer
data
ACK
(Acknowledge
)
A signal driven by an initiator to indicate an
acknowledgement for REQ/ACK data transfer
handshake
ATN
(Attention)
A signal driven by an initiator to indicate the
ATTENTION condition