zl50058 Zarlink Semiconductor, zl50058 Datasheet - Page 60

• Manufacturer Part Number: zl50058
• Description: 12 K Channel Digital Switch With High Jitter Tolerance, Per Stream Rate Conversion 2, 4, 8, 16 Or 32 Mbps , 48 Input And 48 Output Streams
• Manufacturer: Zarlink Semiconductor

12.2
The 8-bit Backplane Data Memory (BDM) has 8,192 positions. The locations are associated with the Backplane
input streams and channels. As explained previously, address bits A13-A0 of the microprocessor define the
addresses of the streams and the channels. The BDM is read-only and configured as follows:
Note that the Backplane Data Memory is actually an 8-bit wide memory. The most significant 8 bits expressed in the
table above are presented to provide 16-bit microprocessor read accesses.
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 16 for Non-32 Mbps Source-to-Local Mode connections, and in Table 17
for 32 Mbps Source-to-Local Mode connections.
The most-significant bit in the memory location, LSRC, selects the switch configuration for Backplane-to-Local or
Local-to-Local. When the per-channel Message Mode is selected (LMM memory bit = HIGH), the lower byte of the
LCM word (LCAB[7:0]) 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
Bit
15
14
13
15:8
Bit
7:0
Backplane Data Memory Bit Definition
Local Connection Memory Bit Definition
LSAB[4:0]
Name
LSRC
LMM
LE
Reserved
Name
BDM
Local 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 (data to be output on channel originated in
Local or Backplane Data Memory).
When HIGH, the channel is in Message Mode (data to be output on channel originated in
Local Connection Memory).
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.
Table 16 - LCM Bits for Non-32 Mbps Source-to-Local Switching
Set to a default value of 8’h00.
Backplane Data Memory - Backplane Input Channel Data.
The BDM[7:0] bits contain the timeslot data from the Backplane side input TDM
stream. BDM[7] corresponds to the first bit received, i.e., bit 7 in ST-BUS mode,
bit 0 in GCI-Bus mode. See Figure 7, ST-BUS and GCI-Bus Input Timing
Diagram for Different Data Rates for the arrival order of the bits
Table 15 - Backplane Data Memory (BDM) Bits
Zarlink Semiconductor Inc.
ZL50057/8
60
Description
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