MT90870AG Zarlink, MT90870AG Datasheet - Page 36

• Manufacturer Part Number: MT90870AG
• Description: Switch Fabric 12K x 12K/8K x 4K 1.8V/3.3V 272-Pin BGA Tray
• Manufacturer: Zarlink

Specifications of MT90870AG

• Package: 272BGA
• Number Of Ports: 32
• Fabric Size: 12K x 12K|8K x 4K
• Switch Core: Non-Blocking|Blocking
• Port Speed: 2.048|4.096|8.192|16.384 Mbps
• Operating Supply Voltage: 1.8|3.3 V

Figure 14, Backplane Port External High Impedance Control Bit Timing (Non-32 Mb/s mode) shows the channel
control bits for BCSTo0, BCSTo1, BCSTo2 and BCSTo3 in one possible scenario which includes stream BSTo0 at
a data-rate of 16.384 Mb/s, BSTo1 at 8.192 Mb/s, BSTo6 at 4.096 Mb/s and BSTo7 at 2.048 Mb/s. All remaining
streams are operated at a data-rate of 16.384 Mb/s.
4.2.2
The data (channel control bit) transmitted by BCSTo0-3 replicates the Backplane Output Enable Bit (BE) of the
Backplane Connection Memory, with a LOW state indicating the channel be set to High Impedance. See Section
12.4, Backplane Connection Memory Bit Definition for setting the Backplane Output Enable Bit (BE).
(16 Mb/s)
BCSTo0
BCSTo1
BCSTo2
BCSTo3
(8 Mb/s)
(2 Mb/s)
(4 Mb/s)
BSTo1
BSTo0
BSTo7
BSTo6
FP8o
C8o
Figure 14 - Backplane Port External High Impedance Control Bit Timing (Non-32 Mb/s mode)
BORS Set LOW, 32 Mb/s Mode
Chan 127
Chan 31
Chan 63
1
Bit 0
Bit 0
Bit 0
0
Chan 0
7
Bit 7
Chan 0 Bit 7
Channel 0
6
Chan 0
5
Bit 6
Channel 0 Bit 7
4
Chan 0
3
Bit 5
Chan 0 Bit 6
2
Zarlink Semiconductor Inc.
Chan 0
1
Bit 4
MT90870
0
36
Chan 127
7
Bit 3
Chan 63 Bit 1
6
One C16o period
Channel 255 bits 7-0
Chan 127
5
Channel 31 Bit 0
Bit 2
4
Chan 127
3
Bit 1
Chan 63 Bit 0
2
Chan 127
1
Bit 0
0
Chan 0
Chan 0
7
Chan 0
Bit 7
Bit 7
Bit 7
Data Sheet
6