MT90820AL1 Zarlink Semiconductor, Inc., MT90820AL1 Datasheet - Page 19

• Manufacturer Part Number: MT90820AL1
• Description: Large Digital Switch
• Manufacturer: Zarlink Semiconductor, Inc.

JTAG Support
The MT90820 JTAG interface conforms to the Boundary-Scan standard IEEE1149.1. This standard specifies a
design-for-testability technique called Boundary-Scan test (BST). The operation of the boundary-scan circuitry is
controlled by an external test access port (TAP) Controller.
Note 1: If bit 13 (MC) of the corresponding connection memory location is 1 (device in message mode), then these entire 8 bits (SAB0, CAB6
- CAB0) are output on the output channel and stream associated with this location.
(Note 1)
(Note 1)
10 - 8,
6 - 0
Bit
15
14
13
12
11
7
LPBK
15
2.048 Mb/s
4.096 Mb/s
8.192 Mb/s
Data Rate
V/C
14
CAB6-0
SAB3-0
MC
Name
LPBK
13
CSTo
V/C
MC
OE
CSTo
Table 14 - CAB Bits Programming for Different Data Rates
12
OE
11
Per Channel Loopback. When 1, the STi n channel m data comes from the STo n
channel m. For proper per channel loopback operations, set the delay offset register
bits OFn[2:0] to zero for the streams which are in the loopback mode. Refer to the
section Loopback Control or Connection Memory Control for more details.
Variable /Constant Throughput Delay. This bit is used to select between the
variable (low) and the constant delay (high) modes on a per-channel basis.
Message Channel. When 1, the contents of the connection memory are output on the
corresponding output channel and stream. Only the lower byte (bit 7 - bit 0) will be
output to the ST-BUS output pins. When 0, the contents of the connection memory
are the data memory address of the switched input channel and stream.
Control ST-BUS output. This bit is output on the CSTo pin one channel early. The
CSTo bit for stream 0 is output first.
Output Enable. This bit enables the ST-BUS output drivers on a per-channel basis.
When 1, the output driver functions normally. When 0, the output driver is in a high-
impedance state.
Source Stream Address Bits. The binary value is the number of the data stream for
the source of the connection.
Source Channel Address Bits. The binary value is the number of the channel for the
source of the connection.
Table 13 - Connection Memory Bits
SAB3
10
CAB Bits Used to Determine the Source Channel of the Connection
SAB2
Zarlink Semiconductor Inc.
9
MT90820
SAB1
8
CAB6 to CAB0 (128 channel/input stream)
CAB4 to CAB0 (32 channel/input stream)
CAB5 to CAB0 (64 channel/input stream)
19
SAB0
7
CAB6
6
Description
CAB5
5
CAB4
4
CAB3
3
CAB2
2
CAB1
1
Data Sheet
CAB0
0