IDT IDT728980

TIME SLOT INTERCHANGE
DIGITAL SWITCH
256 x 256
FEATURES:
•
•
•
•
•
•
•
•
•
IDT728980
outputs, each of which consists of 32 channels (64 Kbit/s per channel) to form
a multiplexed 2.048 Mb/s stream.
256 x 256 channel non-blocking switch
Serial Telecom Bus Compatible (ST-BUS®)
8 RX inputs—32 channels at 64 Kbit/s per serial line
8 TX output—32 channels at 64 Kbit/s per serial line
Three-state serial outputs
Microprocessor Interface (8-bit data bus)
5V Power Supply
Available in 44-pin Plastic Leaded Chip Carrier (PLCC), 40-pin
Plastic Dip (P-DIP) and 44-pin Plastic Quad Flatpack (PQFP)
Operating Temperature Range -40°°C to +85°°C
FUNCTIONAL DESCRIPTION
A functional block diagram of the IDT728980 device is shown on below. The
serial ST-BUS® streams operate continuously at 2.048 Mb/s and are arranged
in 125µs wide frames each containing 32, 8-bit channels. Eight input (RX0-7)
and eight output (TX0-7) serial streams are provided in the IDT728980 device
allowing a complete 256 x 256 channel non-blocking switch matrix to be
constructed. The serial interface clock (C4i) for the device is 4.096 MHz.
The received serial data is internally converted to a parallel format by the on
chip serial-to-parallel converters and stored sequentially in a 256-position Data
Memory. By using an internal counter that is reset by the input 8 KHz frame pulse,
F0i, the incoming serial data streams can be framed and sequentially addressed.
Data to be output on the serial streams may come from two sources: Data
Memory or Connection Memory. The Connection Memory is 16 bits wide and
DESCRIPTION:
The IDT728980 is a ST-BUS® compatible digital switch controlled by a
microprocessor. The IDT728980 can handle as many as 256, 64 Kbit/s input
and output channels. Those 256 channels are divided into 8 serial inputs and
FUNCTIONAL BLOCK DIAGRAM
C4i
F0i
VCC
Timing
Unit
RX0
TX0
Output MUX
RX1
RX2
RX3
RX4
ODE
GND
TX1
TX2
Receive
Serial Data
Streams
RX5
Transmit
Serial Data
Streams
Data
Memory
Control Register
RX6
RX7
Connection
Memory
TX3
TX4
TX5
TX6
Microprocessor Interface
TX7
5706 drw01
DS CS R/W A0/ DTA D0/
A5
D7
CCO
JANUARY 2001
1
 2001 Integrated Device Technology, Inc.
DSC-5706/1
IDT728980 Time Slot Interchange
Digital Switch 256 x 256
Commercial Temperature Range
39
TX3
8
38
TX4
RX5
9
37
RX6
10
RX7
TX1
TX2
DNC(1)
36
35
34
ODE
TX0
37
39
RX0
DTA
CCO
41
40
38
RX2
RX1
42
40
7
RX4
DNC(1)
TX2
DNC(1)
41
RX3
44
TX1
42
INDEX
43
ODE
TX0
43
CCO
44
DTA
2
1
RX1
RX0
3
RX2
4
DNC(1)
6
INDEX
5
PIN CONFIGURATION
RX3
1
33
TX3
RX4
2
32
TX4
TX5
RX5
3
31
TX5
36
TX6
RX6
4
30
TX6
RX7
VCC
5
29
TX7
6
28
GND
27
C4i
14
32
D1
C4i
A0
8
26
D0
D1
9
25
D2
A1
10
24
D3
A2
11
23
D4
TX2
RX4
6
35
TX3
RX5
7
34
TX4
RX6
8
33
TX5
RX7
9
32
TX6
VCC
10
31
TX7
F0i
11
30
GND
C4i
12
29
D0
A0
13
28
D1
A1
14
27
D2
A2
15
26
D3
A3
16
25
D4
A4
17
24
D5
A5
18
23
D6
DS
19
22
D7
R/W
20
21
CS
DNC(1)
D5
D6
D7
CS
DS
R/W
A5
A4
A3
DNC(1)
PLCC: 0.05in. pitch, 0.65in. x 0.65in.
(J44-1, order code: J)
TOP VIEW
NOTE:
1. DNC - Do Not Connect.
5706 drw03
DNC(1)
TX1
36
D5
37
5
D6
4
RX3
CS
D7
RX2
5706 drw02
A5
38
DS
R/W
3
TX0
A4
RX1
A3
D4
DNC(1)
29
28
17
27
A2
26
ODE
25
CCO
39
24
40
2
22
1
RX0
23
DTA
D3
21
D2
30
20
31
16
19
15
18
A0
A1
22
7
20
F0i
21
D0
19
33
17
13
18
F0i
15
GND
16
12
14
TX7
34
12
35
13
11
VCC
PQFP: 0.80mm pitch, 10mm x 10mm
(DB44-1, order code: DB)
TOP VIEW
5706 drw04
PLASTIC DIP: 0.10in. pitch, 2.05in. x 0.60in.
(P40-1, order code: P)
TOP VIEW
PIN DESCRIPTIONS
SYMBOL
GND
VCC
DTA
RX0-7
F0i
C4i
A0-A5
DS
R/W
NAME
Ground.
VCC
Data Acknowledgment
(Open Drain)
RX Input 0 to 7
Frame Pulse
Clock
Address 0 to 5
Data Strobe
I/O
O
I
I
I
I
I
Read/Write
Chip Select
Data Bus 0 to 7
I
I
I/O
O
ODE
TX Outputs 0 to 7
(Three-state Outputs)
Output Drive Enable
CCO
Control Channel Output
O
CS
D0-D7
TX0-7
I
DESCRIPTION
Ground Rail.
+5.0 Volt Power Supply.
This active LOW output indicates that a data bus transfer is complete. A pull-up resistor is required at this
output.
Serial data input streams. These streams have 32 channels at data rates of 2.048 Mb/s.
This input identifies frame synchronization signals formatted to ST-BUS® specifications.
4.096 MHz serial clock for shifting data in and out of the data streams.
These lines provide the address to IDT728980 internal registers.
This is the input for the active HIGH data strobe on the microprocessor interface. This input operates with
CS to enable the internal read and write generation.
This input controls the direction of the data bus lines (D0-D7) during a microprocessor access.
Active LOW input enabling a microprocessor read or write of control register or internal memories.
These pins provide microprocessor access to data in the internal control register. Connection Memory HIGH,
Connection Memory LOW and data memory.
Serial data output streams. These streams are composed of 32, 64 Kbit/s channels at data rates of 2.048 Mb/s.
This is an output enable for the TX0-7 serial outputs. If this input is LOW, TX0-7 are high-impedance. If this is
HIGH, each channel may still be put into high-impedance by software control.
This output is a 2.048 Mb/s line which contains 256 bits per frame. The level of each bit is controlled by the
contents of the CCO bit in the Connection Memory HIGH locations.
2
IDT728980 Time Slot Interchange
Digital Switch 256 x 256
Commercial Temperature Range
FUNCTIONAL DESCRIPTION (Cont'd)
movement within the stream from channel to channel. Data received on an input
stream must first be stored in Data Memory before it is sent out.
As information enters the IDT728980 it must first pass through an internal
serial-to-parallel converter. Likewise, before data leaves the device, it must
pass through the internal parallel-to-serial converter. This data preparation has
an effect on the channel positioning in the frame immediately following the
incoming frame-mainly, data cannot leave in the same time slot, or in the time
slot immediately following. Therefore, information that is to be output in the same
channel position as the information is input, relative to the frame pulse, will be
output in the following frame. As well, information switched to the channel
immediately following the input channel will not be output in the time slot
immediately following, but in the next timeslot allocated to the output channel, one
frame later.
Whether information can be output during a following timeslot after the
information entered the IDT728980 depends on which RX stream the channel
information enters on and which TX stream the information leaves on. This is
caused by the order in which input stream information is placed into Data Memory
and the order in which stream information is queued for output. Table 1 shows
the allowable input/output stream combinations for the minimum 2 channel delay.
is split into two 8-bit blocks—Connection Memory HIGH and Connection
Memory LOW. Each location in Connection Memory is associated with a
particular channel in the output stream so as to provide a one-to-one correspondence between the two memories. This correspondence allows for per channel
control for each TX output stream. In Processor Mode, data output on the TX
stream is taken from the Connect Memory Low and originates from the
microprocessor (Figure 2). Where as in Connection Mode (Figure 1), data is
read from Data Memory using the address in Connection Memory. Data
destined for a particular channel on the serial output stream is read during the
previous channel time slot to allow time for memory access and internal parallelto-serial conversion.
CONNECTION MODE
In Connection Mode, the addresses of input source for all output channels
are stored in the Connect Memory Low. The Connect Memory Low locations
are mapped to corresponding 8-bit x 32-channel output. The contents of the
Data Memory at the selected address are then transferred to the parallel-toserial converters. By having the output channel to specify the input channel
through the connect memory, input channels can be broadcast to several output
channels.
SOFTWARE CONTROL
If the A5 address line input is LOW then the IDT728980 Internal Control
Register is addressed. If A5 input line is high, then the remaining address input
lines are used to select the 32 possible channels per input or output stream. The
address input lines and the Stream Address bits (STA) of the Control register
give the user the capability of selecting all positions of IDT728980 Data and
Connection memories. The IDT728980 memory mapping is illustrated in
Table 2 and Figure 3.
The data in the control register (Table 3) consists of Memory Select and
Stream Address bits, Split Memory and Processor Mode bits. In Split Memory
mode (Bit 7 of the Control register) reads are from the Data Memory and writes
are to the Connect Memory as specified by the Memory Select Bits (Bits 4 and
3 of the Control Register). The Memory Select bits allow the Connect Memory
High or LOW or the Data Memory to be chosen, and the Stream Address bits
define internal memory subsections corresponding to input or output streams.
The Processor Enable bit (bit 6) places EVERY output channel on every
output stream in Processor Mode; i.e., the contents of the Connect Memory LOW
(CML, see Table 5) are output on the TX output streams once every frame
unless the ODE input pin is LOW. If PE bit is HIGH, then the IDT728980 behaves
as if bits 2 (Channel Source) and 0 (Output Enable) of every Connect Memory
High (CMH) locations were set to HIGH, regardless of the actual value. If PE
is LOW, then bit 2 and 0 of each Connect Memory High location operates
normally. In this case, if bit 2 of the CMH is HIGH, the associated TX output
channel is in Processor Mode. If bit 2 of the CMH is LOW, then the contents of
the CML define the source information (stream and channel) of the time slot that
is to be switched to an output.
PROCESSOR MODE
In Processor Mode the CPU writes data to specific Connect Memory Low
locations which are to be output on the TX streams. The contents of the Connect
Memory Low are transferred to the parallel-to-serial converter one channel
before it is to be output and are transmitted each frame to the output until it is
changed by the CPU.
CONTROL
The Connect Memory High bits (Table 4) control the per-channel functions
available in the IDT728980. Output channels are selected into specific modes
such as: Processor Mode or Connection mode and Output Drivers Enabled
or in three-state condition. There is also one bit to control the state of the CCO
output pin.
OUTPUT DRIVE ENABLE (ODE)
The ODE pin is the master output control pin. If the ODE input is held LOW
all TDM outputs will be placed in high impedance regardless Connect Memory
High programming. However, if ODE is HIGH, the contents of Connect Memory
High control the output state on a per-channel basis.
DELAY THROUGH THE IDT728980
The transfer of information from the input serial streams to the output serial
streams results in a delay through the device. The delay through the IDT728980
device varies according to the combination of input and output streams and the
RX
Receive
Serial Data
Streams
Data
Memory
Connection
Memory
Transmit
Serial Data
Streams
Receive
Serial Data
Streams
TX
Data
Memory
Connection
Memory
Transmit
Serial Data
Streams
TX
5706 drw06
Microprocessor
5706 drw05
Figure 2. Processor Mode
Figure 1. Connection Mode
3
IDT728980 Time Slot Interchange
Digital Switch 256 x 256
Commercial Temperature Range
If the ODE input pin is LOW, then all the serial outputs are high-impedance.
If ODE is HIGH, then bit 0 (Output Enable) of the CMH location enables (if HIGH)
or disables (if LOW) the output stream and channel.
The contents of bit 1 (CCO) of each Connection Memory High Location (see
Table 4) is output on CCO pin once every frame. The CCO pin is a 2.048 Mb/s
output, which carries 256 bits. If CCO bit is set HIGH, the corresponding bit on
CCO output is transmitted HIGH. If CCO is LOW, the corresponding bit on the
CCO output is transmitted in LOW. The contents of the 256 CCO bits of the CMH
are transmitted sequentially on to the CCO output pin and are synchronous to
the TX streams. To allow for delay in any external control circuitry the contents
of the CCO bit is output one channel before the corresponding channel on the
TX streams. For example, the contents of CCO bit in position 0 (corresponding
to TX0, CH0) is transmitted synchronously with the TX channel 31, bit 7. Bit 1's
of CMH for channel 1 of stream 0-7 are output synchronously with TX channel
0 bits 7-0.
Input
Output Stream
0
1,2,3,4,5,6,7
1
2
3
4
5
6
7
3,4,5,6,7
5,6,7
7
1,2,3,4,5,6,7
3,4,5,6,7
5,6,7
7
INITIALIZATION OF THE IDT728980
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 TX
outputs are tied together to form matrices. The ODE pin should be held low on
power up to keep all outputs in the high impedance condition until the contents
of the CMH are programmed.
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 connected TX
outputs drive the bus simultaneously. With the CMH setup, the microprocessor
controlling the matrices can bring the ODE signal high to relinquish high
impedance state control to the Connection Memory High bits outputs.
A5 A4 A3 A2 A1 A0
LOCATION
0
1
1
X
0
0
X
0
0
X
0
0
X
0
0
X
0
1
00-1F
20
21
Control Register(1)
Channel 0(2)
Channel 1(2)
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
1
1
1
1
1
1
3F
Channel 31(2)
NOTES:
1. Writing to the Control Register is the only fast transaction.
2. Memory and stream are specified by the contents of the Control Register.
Table 1. Input Stream to Output Stream Combinations that can Provide the
Minimum 2-Channel Delay
Control Register
HEX ADDRESS
CRb7
CRb6
The Control Register is only accessed when A5=0.
All other address bits have no effect when A5=0.
When A5 =1, only 32 bytes are randomly accessable via
A0-A4 at any one instant. Which 32 bytes are
accessed is determined by the state of CRb0 -CRb4.
The 32 bytes correlate to 32 channel of one ST-BUS
stream.
CRb5
CRb4
0
1
1
Table 2. Address Mapping
CRb4
CRb3
CRb2
CRb1
CRb0
CRb3
1
0
1
Connection Memory High
Connection Memory Low
Data Memory
CRb2
CRb1
Channel 31
Channel 31
Channel 31
Channel 31
Channel 31
Channel 31
Channel 31
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
111111
External Address Bits
Channel 0
Channel 1
Channel 2
Channel 31
Channel 0
Channel 0
Channel 0
Channel 0
Channel 0
Channel 0
Channel 0
Channel 1
Channel 1
Channel 1
Channel 1
Channel 1
Channel 1
Channel 1
Channel 2
Channel 2
Channel 2
Channel 2
Channel 2
Channel 2
Channel 2
100000
100001
100010
CRb0 Stream
0
0
1
1
2
0
1
0
1
3
4
5
0
1
6
7
A5-A0
5706 drw07
Figure 3. Address Mapping
4
IDT728980 Time Slot Interchange
Digital Switch 256 x 256
Commercial Temperature Range
Mode Control
Bits
7
Bit
6
(unused)
Memory Select
Bits
5
4
Name
3
Stream Address Bits
2
1
0
Description
7
SM (Split Memory)
When 1, all subsequent reads are from the Data Memory and writes are to the Connection Memory LOW, except
when the Control Register is accessed again. When 0, the Memory Select bits specify the memory for the
operations. In either case, the Stream Address Bits select the subsection of the memory which is made available.
6
PE (Processor Mode)
When 1, the contents of the Connection Memory LOW are output on the Serial Output streams except when the ODE
pin is LOW. When 0, the Connection Memory bits for each channel determine what is output.
5
unused
4-3
MS1-MS0
(Memory Select Bits)
0-0 - Not to be used.
0-1 - Data Memory (read only from the microprocessor port)
1-0 - Connection Memory LOW
1-1 - Connection Memory is HIGH
2-0
STA2-0
(Stream Address Bits)
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.
Table 3. Control Register Configuration
No Corresponding Memory
- These bits give 0s if read
7
Bit
6
5
4
Name
Per Channel Control Bits
3
2
1
0
Description
2
CS (Channel Source)
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.
1
CCO (CCO Bit)
This bit is output on the CCO pin one channel early. The CCO bit for stream 0 is output first.
0
OE (Output Enable)
If the ODE pin is HIGH and bit 6 of the Control Register is 0, then this bit enables the output drive for the location's
channel and stream. This allows individuals channels on individuals streams to be made high-impedance, allowing
switching matrices to be constructed. A 1 enables the driver and a 0 disables it.
Table 4. Connection Memory High Register
Stream Address Bits
7
Bit
6
Channel Address Bits
5
4
Name
3
2
1
0
Description
7-5(1) Stream Address Bits
The number expressed in binary notation on these 3 bits are the number of the stream for the source of the connection.
Bit 7 is the most significant bit, e.g., If bit 7 is 1, bit 6 is 0 and bit 5 is 0 then the source of the connection is a channel on
RX4.
4-0(1) Channel Address Bits
The number expressed in binary notation on these 5 bits is the number of the channel which is the source of the
connection (the stream where the channel lies is defined by bits 7, 6 and 5). Bit 4 is the most significant bit, e.g., if bit 4
is 1, bit 3 is 0, bit 2 is 0, bit 1 is 1 and bit 0 is 1, then the source of the connection is channel 19.
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
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.
Table 5. Connection Memory Low Register
5
IDT728980 Time Slot Interchange
Digital Switch 256 x 256
Commercial Temperature Range
ABSOLUTE MAXIMUM RATINGS
Symbol
Vi
Parameter
Min.
Max.
Unit
VCC - GND
-0.3
7
V
GND - 0.3
VCC +0.3
V
Voltage on Digital Inputs
VO
Voltage on Digital Outputs
IO
Current at Digital Outputs
TS
Storage Temperature
PD
Package Power Dissapation
GND - 0.3
-65
RECOMMENDED OPERATING
CONDITIONS
(1)
VCC +0.3
V
40
mA
+150
°C
2
W
Symbol
Parameter
Typ.(1)
Max.
4.75

5.25
V
0

VCC
V
-40

+85
°C
Min.
VCC
Positive Supply
VI
Input Voltage
TOP
Operating Temperature
Commercial
Unit
NOTE:
1. Typical figures are at 25°C and are for design aid only; not guaranteed and not subject
to production testing.
NOTE:
1. Exceeding these values may cause permanent damage. Functional operation
under these conditions is not implied.
DC ELECTRICAL CHARACTERISTICS
Symbol
Parameter
Typ.(1)
Min.
Max.
Units
Test Conditions
Outputs Unloaded
ICC
Supply Current

7
10
mA
VIH
Input High Voltage
2.0


V
VIL
Input Low Voltage


0.8
V
IIL
Input Leakage


5
µA
CI
Input Capacitance

8

pF
VOH
Output High Voltage
2.4


V
IOH = 10mA
IOH
Output High Current
10
15

mA
Sourcing. VOH = 2.4V
VOL
Output Low Voltage


0.4
V
IOL = 5mA
IOL
Output Low Current
5
10

mA
Sinking. VOL = 0.4V
IOZ
High Impedance Leakage


5
µA
VO between GND and VCC
CO
Output Pin Capacitance

8

pF
NOTE:
1. Typical figures are at 25°C and are for design aid only; not guaranteed and not subject to production testing.
Test Point
VCC
S1 is open circuit except when testing output
levels or high impedance states.
RL
Output
Pin
S1
S2
S2 is switched to VCC or GND when testing
output levels or high impedance states.
CL
GND
GND
5706 drw08
Figure 4. Output Load
6
VI between GND and VCC
IDT728980 Time Slot Interchange
Digital Switch 256 x 256
Commercial Temperature Range
AC ELECTRICAL CHARACTERISTICS
(1)
 CLOCK TIMING
Symbol
Characteristics
Min.
Typ.(2)
Max.
Unit
tCLK
Clock Period(3)
220
244
300
ns
tCH
Clock Width High
95
122
150
ns
tCL
Clock Width Low
110
122
150
ns
ns
tCTT
Clock Transition Time

20

tFPS
Frame Pulse Setup Time
20

200
ns
tFPH
Frame Pulse Hold Time
0.020

50
µs
tFPW
Frame Pulse Width

244

ns
NOTE:
1. Timing is over recommended temperature and power supply voltages.
2. Typical figures are at 25°C and are for design aid only; not guaranteed and not subject to production testing.
3. Contents of Connection Memory are not lost if the clock stops, however, TX outputs go into the high impedance state.
C4i
F0i
Channel 31
Bit 0
Bit Cells
Channel 0
Bit 7
5706 drw09
Figure 5. Frame Alignment
tCLK
tCTT
tCTT
tCHL
tCL
t CH
C4i
((
))
tFPH
tFPS
tFPH
tFPS
tFPW
F0i
5706 drw10
Figure 6. Clock Timing
7
IDT728980 Time Slot Interchange
Digital Switch 256 x 256
Commercial Temperature Range
AC ELECTRICAL CHARACTERISTICS
Symbol
Characteristics
(1)
 SERIAL STREAM TIMING
Min.
Typ.(2)
Max.
Unit
Test Conditions
20
30
60
ns
RL = 1KΩ(3), CL = 150pF
tTAZ
TX0-7 Delay - Active to High Z
tTZA
TX0-7 Delay - High Z to Active
25
45
70
ns
CL = 150pF
tTAA
TX0-7 Delay - Active to Active
30
45
70
ns
CL = 150pF
tTOH
TX0-7 Hold Time
25
45

ns
CL = 150pF
tOED
Output Driver Enable Delay

40
70
ns
RL = 1KΩ(3), CL = 150pF
tXCH
External Control Hold Time
0
10

ns
CL = 150pF
tXCD
External Control Delay

20
40
ns
CL = 150pF
tSIS
Serial Input Setup Time

-40
-20
ns
tSIH
Serial Input Hold Time
90


ns
NOTE:
1. Timing is over recommended temperature and power supply voltages.
2. Typical figures are at 25°C and are for design aid only; not guaranteed and not subject to production testing.
3. High Impedance is measured by pulling to the appropriate rail with RL, with timing corrected to cancel time taken to discharge CL.
Bit Cell Boundary
ODE
C4i
tOED
tOED
tTAZ
tTOH
TX0-7
5706 drw12
TX0-7
Figure 8. Output Driver Enable
tTZA
TX0-7
tTAA
tTOH
Bit Cell Boundaries
TX0-7
C4i
t XCD
tSIS
t XCH
CCO
tSIH
RX0-7
5706 drw11
5706 drw13
Figure 7. Serial Outputs and External Control
Figure 9. Serial Inputs
8
IDT728980 Time Slot Interchange
Digital Switch 256 x 256
Commercial Temperature Range
AC ELECTRICAL CHARACTERISTICS
Symbol
Characteristics
(1)
 PROCESSOR BUS
Min.
Typ.(2)
Max.
Unit
tCSS
Chip Select Setup Time
10
0

ns
tRWS
Read/Write Setup Time
10


ns
tADS
Address Setup Time
10


ns
tAKD
Acknowledgment Delay Fast

30
60
ns
CL = 150pF
tAKD
Acknowledgment Delay Slow
2.7

7.2
cycles
C4i cycles(4)
tFWS
Fast Write Data Setup Time
20


ns
tSWD
Slow Write Data Delay

2.0
1.7
cycles
C4i cycles
tRDS
Read Data Setup Time


0.5
cycles
C4i cycles, CL = 150pF
tDHT
Data Hold Time Read
20


ns
RL = 1KΩ(3), CL = 150pF
tDHT
Data Hold Time Write
20
10

ns
tRDZ
Read Data to High Impedance

30
60
ns
tCSH
Chip Select Hold Time
0


ns
tRWH
Read/Write Hold Time
0


ns
tADH
Address Hold Time
0


ns
tAKH
Acknowledgment Hold Time
10
20
40
ns
Test Conditions
RL = 1KΩ(3), CL = 150pF
RL = 1KΩ(3), CL = 150pF
NOTE:
1. Timing is over recommended temperature and power supply voltages.
2. Typical figures are at 25°C and are for design aid only; not guaranteed and not subject to production testing.
3. High Impedance is measured by pulling to the appropriate rail with RL, with timing corrected to cancel time taken to discharge CL.
4. Processor accesses are dependent on the C4i clock, and so some things are expressed as multiples of the C4i.
DS
tCSS
t CSH
tRWS
tRWH
tADS
t ADH
CS
R/W
A5-A0
tAKD
tAKH
DTA
t RDS
tSWD
tFWS
tRDZ
tDHT
D7-D0
5706 drw14
Figure 10. Processor Bus
9
ORDERING INFORMATION
IDT
XXXXXX
XX
Device Type
Package
X
Process/
Temperature
Range
BLANK
Commercial (-40°C to +85°C)
J
P
DB
Plastic Leaded Chip Carrier (PLCC, J44-1)
Plastic Dip (P40-1)
Plastic Quad Flatpack (PQFP, DB44-1)
728980
256 x 256  Time Slot Interchange Digital Switch
5706 drw15
DATASHEET DOCUMENT HISTORY
5/23/2000
8/18/2000
01/24/2001
pgs. 1, 2, and 10.
pgs. 1, 2, and 10.
pgs. 1 and 6.
CORPORATE HEADQUARTERS
2975 Stender Way
Santa Clara, CA 95054
for SALES:
800-345-7015 or 408-727-6116
fax: 408-492-8674
www.idt.com*
for Tech Support:
408-330-1753
email: [email protected]
P Pkg: www.idt.com/docs/PSC4003.pdf
J Pkg: www.idt.com/docs/PSC4008.pdf
DB Pkg: www.idt.com/docs/PSC4082.pdf
*To search for sales office near you, please click the sales button found on our home page or dial the 800# above and press 2.
The IDT logo is a registered trademark of Integrated Device Technology, Inc. and the ST-BUS® is a trademark of Mitel Corp.
10