mt90870ag2 Zarlink Semiconductor, mt90870ag2 Datasheet - Page 49

• Manufacturer Part Number: mt90870ag2
• Description: Flexible 12 K Digital Switch F12kdx
• Manufacturer: Zarlink Semiconductor

12.3
The Local Connection Memory (LCM) has 4,096 addresses of 16-bit words. Each address, accessed through bits
A13-A0 of the microprocessor port, is allocated to an individual Local output stream and channel. The bit definition
for each 16-bit word is presented in Table 11 for Local-to-Local and Backplane (Non-32 MB/s Mode)-to-Local
connections, and in Table 12, for Local-to-Local and Backplane(32 Mb/s Mode)-to-Local connections. Bit LSRC
selects the switch configuration for Backplane-to-Local or Local-to-Local. When the per-channel Message Mode is
selected (LMM = HIGH), the lower byte of the LCM word (LCAB7-0) will be transmitted as data on the output
stream (LSTo0-15) in place of data defined by the Source Control, Stream and Channel Address bits.
12-8
12-9
7-0
Bit
8-0
Bit
15
14
13
15
14
13
Table 11 - LCM Bits for Local-to-Local and Backplane (Non-32 Mb/s Mode)-to-Local Switching
Local Connection Memory Bit Definition
LSAB4-0
LCAB7-0
Name
LSRC
LMM
LE
LSAB3-0
LCAB8-0
Name
LSRC
LMM
LE
Table 12 - LCM Bits for Backplane(32 Mb/s Mode)-to-Local Switching
Source Control Bit
When LOW, the source is from the Backplane input port (Backplane Data Memory).
When HIGH, the source is from the Local input port (Local Data Memory).
Ignored when LMM is set HIGH.
Local Message Mode Bit
When LOW, the channel is in Connection Mode.
When HIGH, the channel is in Message Mode.
Local Output Enable Bit
When LOW the channel may be high impedance, either at the device output, or set by an
external buffer dependent upon the LORS pin. When HIGH the channel is active.
Source Stream Address Bits
The binary value of these 5 bits represents the input stream number.
Ignored when LMM is set HIGH.
Source Channel Address Bits
The binary value of these 8 bits represents the input channel number when LMM is set
LOW. Transmitted as data when LMM is set HIGH.
Source Control Bit.
When LOW, the source is from the Backplane input port (Backplane Data Memory).
When HIGH, the source is from the Local input port (Local Data Memory).
Ignored when LMM is set HIGH.
Local Message Mode Bit
When LOW, the channel is in Connection Mode.
When HIGH, the channel is in Message Mode.
Local Output Enable Bit
When LOW, the channel may be high impedance, either at the device output or set by an
external buffer, dependent upon the LORS pin. When HIGH, the channel is active.
Source Stream Address Bits.
The binary value of these 4 bits represents the input stream number.
Ignored when LMM is set HIGH.
Channel Address Bits.
The binary value of these 9 bits represents the input channel number, when LMM is LOW.
Bits LCAB7-0 transmitted as data when LMM is set HIGH.
Zarlink Semiconductor Inc.
MT90870
49
Description
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