MT8986 Mitel Semiconductor, MT8986 Datasheet - Page 12

• Manufacturer Part Number: MT8986
• Description: CMOS ST-BUS FAMILY Multiple Rate Digital Switch
• Manufacturer: Mitel Semiconductor

MT8986
CMH is transmitted during ST-BUS channel 31 bit
6.
For more detailed description of the CSTo
operation, see section 6 of Application Note MSAN-
123.
The Bit V/C (Variable/Constant Delay) of each
Connect Memory High location allows the per-
channel selection between Variable and Constant
throughput delay modes.
Initialization of the MT8986
On initialization or power up, the contents of the
Connection Memory High can be in any state. This
is a potentially hazardous condition when multiple
MT8986 ST-BUS outputs are tied together to form
matrices, as these outputs may conflict. The ODE
pin should be held low on power up to keep all
outputs in the high impedance condition.
During the microprocessor initialization routine, the
microprocessor should program the desired active
paths through the matrices, and put
all other
channels into the high impedance state.
Care
should be taken that no two ST-BUS outputs drive
the bus simultaneously.
When this process is
complete,
the
microprocessor
controlling
the
matrices can bring the ODE signal high to relinquish
high impedance state control to the CMH
0s.
b
2-74