ZL50020

The ZL50020 is a maximum 2048 x 2048 channel non-blocking digital Time Division Multiplex (TDM) switch. It has thirty-two input streams (STi0 - 31) and thirty-two output streams (STio0 - 31). The device can switch 64kbps and Nx64kbps TDM channels from any input stream to any output stream. Each of the input and output streams can be independently programmed to operate at any of the following data rates: 2.048Mbps, 4.096Mbps, 8.192Mbps or 16.384Mbps. The ZL50020 provides up to sixteen high impedance control outputs (STOHZ0 - 15) to support the use of external tristate drivers for the first sixteen output streams (STio0 - 15). The output streams can be configured to operate in bi-directional mode, in which case STi0 - 31 will be ignored.

The ZL50020 contains two types of internal memory - data memory and connection memory. There are four modes of operation - Connection Mode, Message Mode, BER mode and high impedance mode. In Connection Mode, the contents of the connection memory define, for each output stream and channel, the source stream and channel (the actual data to be output is stored in the data memory). In Message Mode, the connection memory is used for the storage of microprocessor data. Using Zarlink's Message Mode capability, microprocessor data can be broadcast to the data output streams on a per-channel basis. This feature of ZL50020 is useful for transferring control and status information for external circuits or other TDM devices. In BER mode the output channel data is replaced with a pseudorandom bit sequence (PRBS) from one of 32 PRBS generators that generates a 2¹⁵-1 pattern. On the input side channels can be routed to one of 32 bit error detectors. In high impedance mode the selected output channel can be put into a high impedance state.   

The configurable non-multiplexed microprocessor port allows users to program ZL50020 operating modes and switching configurations. Users can employ the microprocessor port to perform register read/write, connection memory read/write, and data memory read operations. The port is configurable to interface with either Motorola or Intel-type microprocessors.

The ZL50020 also supports the mandatory requirements of the IEEE-1149.1 (JTAG) standard via the test port.