Motorola MVME712A 用户手册

Support Information

3-12

33

DB07*

DATA bus (bit 7) - most signiÞcant bit and the 
highest priority during the arbitration phase. 

34

DBP*

DATA bus (parity) - data parity is odd. Use of 
parity is a system option. Parity is not valid 
during the arbitration phase. 

35-37

GND

GROUND 

38

TERMPWR

TERMINATOR POWER 

39,40

GND

GROUND 

41

ATN*

ATTENTION - signal driven by the initiator. 
Indicates the attention condition. 

42

GND

GROUND 

43

BSY*

BUS BUSY - OR-tied signal that indicates that 
the bus is being used. 

44

ACK*

ACKNOWLEDGE - signal driven by an initiator 
to indicate an acknowledgment for a REQ/ACK 
data transfer handshake. 

45

RST*

RESET - OR-tied signal that indicates the RESET 
condition. 

46

MSG*

MESSAGE - signal driven by the target during 
the message phase. 

47

SEL*

SELECT - signal used by an initiator to select a 
target or by a target to reselect an initiator. 

48

D/C*

DATA/COMMAND - signal driven by the 
target. It indicates whether command or data 
information is on the data bus. True (low) 
indicates command. 

49

REQ*

REQUEST - signal driven by a target to indicate 
a request for a REQ/ACK data transfer 
handshake. 

50

O/I*

OUTPUT/INPUT - signal driven by a target that 
controls the direction of data movement on the 
bus. True (low) indicates input to the initiator. 
False (high) indicates output from the initiator. 
This signal is also used to distinguish between 
selection and reselection phases.