ZL50020 Datasheet, PDF (16/83 Pages) Zarlink Semiconductor Inc – Enhanced 2 K Digital Switch

ZL50020
Data Sheet
3.0 Device Overview
The device has thirty-two ST-BUS/GCI-Bus inputs (STi0 - 31) and thirty-two ST-BUS/GCI-Bus outputs (STio0 - 31).
STio0 - 31 can also be configured as bi-directional pins, in which case STi0 - 31 will be ignored. It is a non-blocking
digital switch with 2048 64 kbps channels and is capable of performing rate conversion between ST-BUS/GCI-Bus
inputs and ST-BUS/GCI-Bus outputs. The ST-BUS/GCI-Bus inputs accept serial input data streams with data rates
of 2.048 Mbps, 4.096 Mbps, 8.192 Mbps and 16.384 Mbps on a per-stream basis. The ST-BUS/GCI-Bus outputs
deliver serial data streams with data rates of 2.048 Mbps, 4.096 Mbps and, 8.192 Mbps and 16.384 Mbps on a
per-stream basis. The device also provides sixteen high impedance control outputs (STOHZ0 - 15) to support the
use of external ST-BUS/GCI-Bus tristate drivers for the first sixteen ST-BUS/GCI-Bus outputs (STio0 -15).
By using Zarlink’s message mode capability, microprocessor data stored in the connection memory can be
broadcast to the output streams on a per-channel basis. This feature is useful for transferring control and status
information for external circuits or other ST-BUS/GCI-Bus devices.
The device uses the ST-BUS/GCI-Bus input frame pulse (FPi) and the ST-BUS/GCI-Bus input clock (CKi) to define
the input frame boundary and timing for sampling the ST-BUS/GCI-Bus input streams with various data rates. The
output data streams will be driven by and have their timing defined by FPi and CKi in Divided Clock mode (CLKM
bit 11 Table 13, Control Register (CR) Bits. In Multiplied Clock mode, the output data streams will be driven by an
internally generated clock, which is multiplied from CKi internally. In Multiplied Clock mode, the output data streams
will be driven by an internally generated clock, which is multiplied from CKi internally. Refer to Application Note
ZLAN-120 for further explanation of the different modes of operation.
There are two clock modes for this device:
The first is the Divided Clock mode. In this mode, output streams are clocked by input CKi. Therefore the output
streams have exactly the same jitter as the input streams. The output data rate can be the same as or lower than
the input data rate, but the output data rate cannot be higher than what CKi can drive. For example, if CKi is
4.096 MHz, the output data rate cannot be higher than 2.048 Mbps.The second clock mode is called Multiplied
Clock mode. In this mode, CKi is used to generate a 16.384 MHz clock internally, and output streams are driven by
this internal clock. In Multiplied Clock mode, the data rate of output streams can be any rate, but output jitter may
not be exactly the same as input jitter.
A Motorola or Intel compatible non-multiplexed microprocessor port allows users to program the device to operate
in various modes under different switching configurations. Users can use the microprocessor port to perform
internal register and memory read and write operations. The microprocessor port has a 16-bit data bus, a 14-bit
address bus and six control signals (MOT_INTEL, CS, DS_RD, R/W_WR and DTA_RDY).
The device supports the mandatory requirements of the IEEE-1149.1 (JTAG) standard via the test port.
4.0 Data Rates and Timing
The ZL50020 has 32 serial data inputs and 32 serial data outputs. Each stream can be individually programmed to
operate at 2.048 Mbps, 4.096 Mbps, 8.192 Mbps or 16.384 Mbps. Depending on the data rate there will be 32
channels, 64 channels, 128 channels or 256 channels, respectively, during a 125 µs frame.
The output streams can be programmed to operate as bi-directional streams. The output streams are divided into
two groups to be programmed into bi-directional mode. By setting BDL (bit 6) in the Internal Mode Selection (IMS)
register, input streams 0 - 15 (STi0 - 15) are internally tied low, and output streams 0 - 15 (STio0 - 15) are set to
operate in a bi-directional mode. Similarly, when BDH (bit 7) in the Internal Mode Selection (IMS) register is set,
input streams 16 - 31 (STi16 - 31) are internally tied low, and output streams 16 - 31 (STio16 - 31) are set to operate
in bi-directional mode. The groups do not have to be set into the same mode. Therefore it is possible to have half of
the streams operating in bi-directional mode while the other half is operating in normal input/output mode.
The input data rate is set on a per-stream basis by programming STIN[n]DR3 - 0 (bits 3 - 0) in the Stream Input
Control Register 0 - 31 (SICR0 - 31). The output data rate is set on a per-stream basis by programming STO[n]DR3
- 0 (bits 3 - 0) in the Stream Output Control Register 0 - 31 (SOCR0 - 31). The output data rates do not have to
match or follow the input data rates. he maximum number of channels switched is limited to 2048 channels. If all 32
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