zl50023 Zarlink Semiconductor, zl50023 Datasheet - Page 28

• Manufacturer Part Number: zl50023
• Description: Enhanced 4 K Channel Tdm Switch With Rate Conversion
• Manufacturer: Zarlink Semiconductor

8.0
The switching of information from the input serial streams to the output serial streams results in a throughput delay.
The device can be programmed to perform timeslot interchange functions with different throughput delay
capabilities on a per-channel basis. For voice applications, select variable throughput delay to ensure minimum
delay between input and output data. In wideband data applications, select constant delay to maintain the frame
integrity of the information through the switch. The delay through the device varies according to the type of
throughput delay selected by the V/C (bit 14) in the Connection Memory Low when CMM = 0.
8.1
Variable delay mode causes the output channel to be transmitted as soon as possible. This is a useful mode for
voice applications where the minimum throughput delay is more important than frame integrity. The delay through
the switch can vary from 7 channels to 1 frame + 7 channels. To set the device into variable delay mode, VAREN
(bit 4) in the Control Register (CR) must be set before V/C (bit 14) in the Connection Memory Low when CMM = 0.
If the VAREN bit is not set and the device is programmed for variable delay mode, the information read on the
output stream will not be valid.
FPi
STio[n]
STOHZ[n]
(Default = No Advancement)
STOHZ[n]
(with Advancement)
Note: n = 0 to 15
Note: Last = Last Channel of 31, 63, 127 and 255 for 2.048 Mbps, 4.096 Mbps, 8.192 Mbps and 16.384 Mbps modes respectively.
Variable Delay Mode
Data Delay Through the Switching Paths
Last
Figure 16 - Channel Switching External High Impedance Control Timing
CH0
Output Frame Boundary
CH1
CH2
HiZ
STOHZ Advancement (Programmable in 4 steps of 1/4 bit
CH3
Zarlink Semiconductor Inc.
for 2.048 Mbps, 4.096 Mbps and 8.192 Mbps
Programmable in 2 steps of 1/2 bit for 16.384 Mbps)
ZL50023
28
Last-2
Last-1
Last
Data Sheet
CH0