MB86604L
s
PIN DESCRIPTION
1. SCSI Interface
Pin
number
60
Symbol
REQ
Pin name
Request
I/O
I/O
Function
Transfer request signal in the information transfer phases from
target to initiator. The input signal to this pin is used for the timing
control of data transfer sequence. This is a three-state I/O pin
and an active low pin.
This pin is for the acknowledge signal from initiator to target for
the REQ signal in the information transfer phases. The input
signal to this pin is used for the timing control of data transfer
sequence. This is a three-state I/O pin and an active low pin.
This pin is for the attention signal that initiator requests target for
the message transfer phase. This is an active-low pin.
This pin is for the message signal that specifies type of
information transferred on the data bus. This is an active-low pin
and becomes “L” when message phase is specified.
This pin is for the control/data signal that specifies type of
information transferred on the data bus. This an active-low pin
and becomes “L” level when command, status, or message
phase is specified.
This pin is for the input/output signal that specifies direction of
information transferred on the data bus. This is an active-low pin.
When this pin is “L” level, the information is transferred from
target to initiator. When this pin is “H” level, the information is
transferred from initiator to target.
This pin is for the SCSI bus busy signal. In the arbitration phase,
this is for the request signal for the use of bus acquisition. This is
an active-low pin.
This pin is for the select signal used by initiator to select target
during the selection phase and by target to reselect initiator
during the reselection phase. This is an active-low pin.
This pin is for the reset signal used by any device on the bus.
When the device is an input operation, the reset signal is input to
this pin. When output operation, the reset signal is output from
this pin. This is an active-low pin.
These pins are for the bidirectional 8-bit SCSI data bus and 1-bit
odd parity line.
68
ACK
Acknowledge
I/O
71
63
ATN
MSG*
Attention
Message
I/O
I/O
61
C/D*
Control/data
I/O
58
I/O*
Input/output
I/O
69
BSY
Busy
I/O
62
SEL
Select
I/O
67
RST
Reset
I/O
11, 12, 13, DB7
17, 18, 19, to
DB0
20, 22
9
DBP
Data bus 7
to
data bus 0
Data bus
parity
I/O
* : Regarding the status of information transfer which is indicated by MSG, C/D, and I/O pins, See Table Phase Status.
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