5
Interface
D
Interface switching
Two interfaces are provided, an 8 —bit parallel Centronics interface
and
RS—232C
interface. These interfaces are automatically switched. The in
terface that receives a signal first after the power is turned on is selected.
2)
8—bit parallel interface (conformable to Centronics)
O) Control signal
ST B
BUSY
ACK
ERROR
Input/output circuit configuration and input/output condition
Input/output
logic level
4.
7k Q
DATA 1
74 HC 132
S
TB
o
o —1.35 v
1000
1500
PF
Output logic level
4. 7kQ
7406
BUSY
ACK
ERROR
Timing chart
0 vs or more
DATA
S
TB
0.1
or less
BUSY
ACK
0.5gs or more
Data holding time
0 .5gs or more
0. vs or more