IDT72V8985 Integrated Device Technology, IDT72V8985 Datasheet - Page 8

• Manufacturer Part Number: IDT72V8985
• Description: 3.3 Volt Time Slot Interchange Digital Switch 256 X 256
• Manufacturer: Integrated Device Technology

TABLE 3      CONTROL REGISTER
NOTE:
1. If bit 2 of the corresponding Connection HIGH location is 1 or bit 6 of the Control Register is 1, then these entire 8 bits are output on the channel and stream associated with
TABLE 4      CONNECTION MEMORY HIGH
TABLE 5      CONNECTION MEMORY LOW
x = don't care
x = don't care
IDT72V8985 3.3V Time Slot Interchange
Digital Switch 256 x 256
7,5,4,3
this location. Otherwise, the bits are used as indicated to define the source of the Connection which is output on the channel and stream associated with this location.
Bit
4-0
Bit
7-5
Bit
4-3
2-0
6
2
1
0
7
6
5
(1)
SAB2-0
(Source Stream Address Bits)
CAB2-0
(Source Channel Address Bits) is present is defined by bits SAB2-0). Bit 4 is the most significant bit.
SM (Split Memory)
PE (Processor Mode)
MS1-MS0
(Memory Select Bits)
STA2-0
(Stream Address Bits)
V/C (Variable/Constant
Throughput Delay Mode)
CS
(Channel Source)
OE (Output Enable)
CCO (CCO Bit)
(1)
(1)
Name
Name
Name
When 1, all subsequent reads are from the Data Memory and writes are to the Connection Memory, except when
the Control Register is accessed again. The Memory Select bits need to specify the memory for the operations.
When 1, the contents of the Connection Memory LOW are output on the Serial Output streams except when in high-
impedance. When 0, the Connection Memory bits for each channel determine what is output.
unused
0-0 - Not to be used.
0-1 - Data Memory (read only from the CPU)
1-0 - Connection Memory LOW
1-1 - Connection Memory is HIGH
The number expressed in binary notation on these bits refers to the input or output stream which corresponds to the
subsection of memory made accessible for subsequent operations.
unused
This bit is used to select between Variable (LOW) and Constant Delay (HIGH) modes on a per-channel basis.
When 1, the contents of the corresponding location in Connection Memory LOW are output on the location's channel
and stream. When 0, the contents of the corresponding location in Connection Memory LOW act as an address for the
Data Memory and determine the source of the connection to the location's channel and stream.
This bit drives a bit time on the CCO output pin.
This bit enables the output drivers on a per-channel basis. This allows individual channels on individual streams to
be made high-impedance, allowing switch matrices to be constructed. A HIGH enables the driver and a LOW disables it.
These three bits are used to select eight source streams for the Connection.
These five bits are used to select 32 different source channels for the Connection (the stream where the channel
SAB2
SM
X
7
7
7
SAB1
V/C
PE
6
6
6
SAB0
X
X
5
5
5
CAB4
8
MS1
X
4
4
4
CAB3
MS0
X
3
3
Description
Description
3
Description
STA2
CAB2
CS
2
2
2
STA1
CAB1
CCO
1
1
1
STA0
CAB0
OE
0
0
0
Commercial Temperature Range