MT90871 Zarlink Semiconductor, MT90871 Datasheet - Page 13

• Manufacturer Part Number: MT90871
• Description: Flexible 8K Digital Switch (F8KDX)
• Manufacturer: Zarlink Semiconductor

Data Sheet
operation, the remaining part of this document assumes the ST-BUS style frame pulse with a single width
frame pulse of 122ns and a falling active clock-edge, unless explicitly stated otherwise.
In addition, the device provides FP8o, FP16o, C8o and C16o outputs to support external devices which
connect to the Local port. The Local frame pulses (FP8o, FP16o) will be provided in the same style as the
master frame pulse (FP8i). The polarity of C8o and C16o, at the Frame Boundary, can be controlled by the
Control Register bit, COPOL. An analog phase lock loop (APLL) is used to multiply the external clock
frequency to generate an internal clock signal operated at 131.072MHz.
2.4
The MT90871 accepts a Backplane Frame Pulse (FP8i) and generates the Local Frame Pulse outputs, FP8o
and FP16o, which are aligned to the master frame pulse. There is a constant three frame delay for data being
switched.
For further details of Frame Pulse conditions and options see section 13.1 "Control Register (CR)", Figure 17,
Frame Boundary Conditions, ST- BUS Operation, and Figure 18, Frame Boundary Conditions, GCI - BUS
Operation.
Figure 8 - Backplane and Local Frame Pulse Alignment for Data Rates of 2Mb/s, 4Mb/s, 8Mb/s
BSTi/BSTo0-15
BSTi/BSTo0-15
BSTi/BSTo0-15
BSTi/BSTo0-15
LSTi/LSTo0-15
LSTi/LSTo0-15
LSTi/LSTo0-15
LSTi/LSTo0-15
(16Mb/s)
(16Mb/s)
Backplane Frame Pulse Input and Local Frame Pulse Output Alignment
(2Mb/s)
(4Mb/s)
(8Mb/s)
(2Mb/s)
(4Mb/s)
(8Mb/s)
FP8o
FP8i
C8o
C8i
CH
CH
CH0
CH0
0
0
CH
CH
1
1
CH0
CH0
CH
CH
CH1
CH1
2
2
CH
CH
3
3
CH0
CH0
CH
CH
CH2
CH2
4
4
CH
CH
5
5
CH1
CH1
Zarlink Semiconductor Inc.
CH
CH
CH3
CH3
6
6
CH
CH
7
7
and 16Mb/s
CH
CH
CH4
CH4
8
8
CH
CH
9
9
CH2
CH2
CH
CH
10
CH5
10
CH5
CH
CH
11
11
CH1
CH1
CH
CH
12
12
CH6
CH6
13
CH
CH
13
CH3
CH3
CH
CH
14
CH7
14
CH7
CH
CH
15
15
CH
CH
16
16
CH8
CH8
CH
17
CH
CH4
CH4
17
CH
CH
18
18
CH9
CH9
CH
CH
19
19
CH2
CH2
CH
CH
20
20
CH10
CH10
CH
21
CH
CH5
CH5
21
CH
CH
22
22
CH11
CH11
CH
CH
23
23
13