MT90840AP Zarlink, MT90840AP Datasheet - Page 25

• 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

4.096 Mbps Mode
The 4.096 Mbps mode has 8 input and 8 output streams, and 64 channels per stream. Therefore 3 bits are used to
address the 8 streams, and 6 bits are used to address the 64 channels. Figure 13a 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 13b shows how the Receive Path Connection Memory is addressed by the CPU in 4.096 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 12b - 2.048 Mbps Add/Drop Mode RPCM Addressing
Figure 13a - 4.096 Mbps TPDM Addressing
Serial
Channel
Serial Input
Channel
STi7 (STo15), Ch30
STi7 (STo15), Ch31
STi0 (STo8), Ch0
STi0 (STo8), Ch1
STi7, Ch62
STi7, Ch63
STi0, Ch0
STi0, Ch1
STo7, Ch30
STi7, Ch31
STo0, Ch0
STo0, Ch1
.
.
Output
.
.
.
.
Zarlink Semiconductor Inc.
TPDM
Address
000H
001H
1FEH
1FFH
MT90840
RPCM
Address
101H
000H
001H
0FEH
0FFH
100H
1FEH
1FFH
25
CPU Port Addressing:
CAR
CPU Port Addressing:
CAR
TPCM Contents:
Bits 8:6 select one of 8 streams.
Bits 5:0 select one of 64 channels per
stream.
Stream
1 0
8 7 6
1 0
Stream
Stream
Address Bus
6
Address Bus
Channel
6 5 4 3 2 1 0
5
5
4 3 2 1 0
4 3 2 1 0
Channel
Channel
Data Sheet