zl50018gag2 Zarlink Semiconductor, zl50018gag2 Datasheet - Page 29

• Manufacturer Part Number: zl50018gag2
• Description: 2 K Digital Switch With Enhanced Stratum 3 Dpll
• Manufacturer: Zarlink Semiconductor

7.0
Various registers are provided to adjust the input delay and output advancement for each input and output data
stream. The input bit delay and output bit advancement can vary from 0 to 7 bits for each individual stream.
If input delay of less than a bit is desired, different sampling points can be used to handle the adjustments. The
sampling point can vary from 1/4 to 4/4 with a 1/4-bit increment for all input streams unless the stream is operating
at 16.384 Mbps, in which case the fractional bit delay has a 1/2-bit increment. By default, the sampling point is set
to the 3/4-bit location for non-16.384 Mbps data rates and the 1/2-bit location for the 16.384 Mbps data rate.
The fractional output bit advancement can vary from 0 to 3/4 bits, again with a 1/4-bit increment unless the output
stream is operating at 16.384 Mbps, in which case the output fractional bit advancement has a 1/2-bit increment
from 0 to 1/2 bit. By default, there is 0 output bit advancement.
Although input delay or output advancement features are available on streams which are operating in bi-directional
mode it is not recommended, as it can easily cause bus contention. If users require this function, special attention
must be given to the timing to ensure contention is minimized.
7.1
The input bit delay programming feature provides users with the flexibility of handling different wire delays when
designing with source streams for different devices.
By default, all input streams have zero bit delay, such that bit 7 is the first bit that appears after the input frame
boundary (assuming ST-BUS formatting). The input delay is enabled by STIN[n]BD2-0 (bits 8 - 6) in the Stream
Input Control Register 0 - 31 (SICR0 - 31) as described in Table 61 on page 93. The input bit delay can range from
0 to 7 bits.
FPi
STi[n]
Bit Delay = 0
(Default)
STi[n]
Bit Delay = 1
Input Bit Delay Programming
Data Input Delay and Data Output Advancement
Note: Last Channel = 31, 63, 127 and 255 for 2.048, 4.096, 8.192 and 16.384 Mbps modes respectively.
4 3
5
Last Channel
Last Channel
4 3
2 1 0
Figure 13 - Input Bit Delay Timing Diagram (ST-BUS)
2 1 0
7
6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 3 2
7
6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 3
Channel 0
Bit Delay = 1
Channel 0
Zarlink Semiconductor Inc.
ZL50018
29
Channel 1
Channel 1
Channel 2
Channel 2
Data Sheet