ISO-CMOS
Pin Description (continued)
Pin #
40
DIP
44
PLCC
MT8981D
Name
Description
22-
24
25-
29
30
31-
34
35
36-
38
39
25-
27
29-
33
34
35-
38
39
41-
43
44
D7-D5
Data 7 to 5 (Three-state I/O Pins).
These are the bidirectional data pins on the
microprocessor interface.
D4-D0
Data 4 to 0 (Three-state I/O Pins).
These are the bidirectional data pins on the
microprocessor interface.
V
SS
IC
Power Input.
Negative Supply (Ground).
Internal Connections.
Leave pins disconnected.
STo3
ST-BUS Output 3 (Three-state Outputs).
These are the pins for the four 2048 kbit/s ST-
BUS output streams.
STo2-
ST-BUS Output 2 to 0 (Three-state Outputs).
These are the pins for the four 2048
STo0 kbit/s ST-BUS output streams.
ODE
Output Drive Enable (Input).
If this input is held high, the STo0-STo3 output drivers function
normally. If this input is low, the STo0-STo3 output drivers go into their high impedance state.
NB:
Even when ODE is high, channels on the STo0-STo3 outputs can go high impedance
under software control.
IC
Internal Connection.
Leave pin disconnected.
40
1
2-19