MT90840AP Zarlink, MT90840AP Datasheet - Page 26

• Manufacturer Part Number: MT90840AP
• Description: Switch Fabric 512 x 2430/512 x 512/2.373K x 2.373K 5V 84-Pin PLCC Tube
• Manufacturer: Zarlink

Specifications of MT90840AP

• Package: 84PLCC
• Number Of Ports: 16
• Fabric Size: 512 x 2430|512 x 512|2.373K x 2.373K
• Switch Core: Non-Blocking
• Port Speed: 8.192|4.096|2.048 Mbps
• Operating Supply Voltage: 5 V

8.192 Mbps Mode
The 8.192 Mbps mode has 4 input and 4 output streams, and 128 channels per stream. Therefore 2 bits are used to
address the 4 streams, and 7 bits are used to address the 128 channels. Figure 14a shows how the Transmit Path
Data Memory is read in this mode. Each of the 512 input channels is mapped to an address in the TPDM. CPU
reads require the 2 LSBs of the CAR Register, and the 7 LSBs of the address bus. The source-channel address-
value written in the TPCM requires 9 bits.
Figure 14b shows how the Receive Path Connection Memory is addressed by the CPU in 8.192 Mbps mode. Each
of the 512 output channels has a control-address in the RPCM. CPU accesses require the 2 LSBs of the CAR
Register, and the 7 LSBs of the address bus. Per-channel direction control in this mode is the same as the 2.048
Mbps Balanced mode.
Figure 14a - 8.192 Mbps TPDM Addressing
Figure 13b - 4.096 Mbps RPCM Addressing
Serial
Channel
Serial Input
Channel
STi3, Ch126
STi4, Ch127
STo7, Ch62
STo7, Ch63
STo0, Ch0
STo0, Ch1
STi0, Ch0
STi0, Ch1
.
.
.
.
Output
Zarlink Semiconductor Inc.
TPDM
Address
000H
001H
1FEH
1FFH
000H
001H
1FEH
1FFH
RPCM
Address
MT90840
26
CPU Port Addressing:
CAR
Stream
1 0
CAR
Bits 8:7 select one of 8 streams.
Bits 6:0 select one of 128 channels
per stream.
TPCM Contents:
Stream Channel
CPU Port Addressing:
1 0
8 7
Stream
Address Bus
6
Address Bus
6
6
5
5
5
Channel
4 3 2 1 0
Channel
4 3 2 1 0
4 3 2 1 0
Data Sheet