User`s manual

SUPPORT INFORMATION
MPC505EVBUM/D 4-3
Table 4-1. SCSI Connector (not populated) (continued)
Pin Mnemonic Signal
27 – 31 GND GROUND
32 ATNI* ATTENTION – Active-low output signal that indicates to the target that
the MPC505 has a message to send.
33 – 35 GND GROUND
36 BSY BUSY – Active low I/O signal that indicates the SCSI is busy.
37 GND GROUND
38 ACK ACKNOWLEDGE – Active-low handshake signal that indicates to the
target that the MPC505 has transfered a byte.
39 GND GROUND
40 RST RESET – Active-low output signal that indicates a reset condition. All
devices using the bus must release it.
41 GND GROUND
42 MSG MESSAGE – Active-low output signal that indicates the target is
sending a message.
43 GND GROUND
44 SEL SELECT – Active-low output signal used by the MPC505 to select a
target.
45 GND GROUND
46 C/D CONTROL/DATA – Active-low output signal that indicates whether
control of data is on the data bus. This signal is controlled by the target.
47 GND GROUND
48 REQ REQUEST – Active-low handshake signal that indicates to the MPC505
that the target has transfered a byte.
49 GND GROUND
50 I/O INPUT/OUTPUT – Active-low output signal driven by the target that
controls data direction.