mt8981dl Mitel, mt8981dl Datasheet - Page 8

• Manufacturer Part Number: mt8981dl
• Description: Iso-cmos St-bus ?amily Digital Switch
• Manufacturer: Mitel

MT8981D
Application Circuit with 6802 Processor
Fig. 10 shows an example of a complete circuit
which may be used to evaluate the chip.
For convenience, a 4 MHz crystal oscillator has been
used rather than a 4.096 MHz clock, as both are
within the limits of the chip’s specifications. The RC
delay used
sufficient hold time for the FP signal, but the values
used may have to be changed if faster 393 counters
become available.
2-24
Controlling
Processor
Micro-
with the
IN 0/3
IN 4/7
Figure 8 - Example Architecture of a Simple Digital Switching System
Figure 9 - Four 8981s Arranged in a Non-Blocking 8 x 8 Configuration
ISO-CMOS
393 counters
Signalling
Control &
Speech
Switch
8981
8981
-
-
ensures a
STo0-3
STi0/3 STo0/3
STi0/3 STo0/3
STi0/3 STo0/3
STi0/3 STo0/3
4
STi0-3
8981
8981
8981
8981
4
#2
#3
#4
#1
STo0-3
4
STi0-3
4
The chip is shown as memory mapped into the
MEK6802D3
correspond to processor addresses 2000-203F.
Delay through the address decoder requires the
VMA signal to be used twice to remove glitches. The
MEK6802D3 board uses a 10K
pin, which would have to be incorporated into the
circuit if the board was replaced by a processor.
with Codec (e.g. 8964)
with Codec (e.g. 8964)
Line Interface Circuit
Line Interface Circuit
Repeated for Lines
2 to 127
•
•
•
system.
OUT 0/3
OUT 4/7
Chip
Line 128
Line 1
Repeated for Lines
addresses
pullup on the MR
2 to 127
•
•
•
00-3F