PM8611

`The PM8611 SBI336 Bus Serializer (SBSLITE? is a:
`Scalable Bandwidth Interconnect (SBI? converter and Time Division Multiplexer (TDM) SBI switch.
`Byte-wide 77.76 MHz SBI336 bus to 777.6 MHz serial SBI336S converter.
`DS0, NxDS0, T1, E1, TVT1.5, TVT2, DS3 and E3 granular SBI336 to serial SBI336S switch. Supports subrate link switching with the restriction that subrate links must be symmetric in both the transmit and receive directions.
`Byte-wide 77.76 MHz TelecomBus to serial 777.6 MHz TelecomBus converter. This requires the TelecomBus J1 byte to be in a fixed location corresponding to a value of 0 or 522 which is immediately following the C1 octets:
`VT1.5, VT2, STS-1 77.76 MHz TelecomBus to serial TelecomBus switch.
`Can be used with the Narrowband Switch Elements, NSE-20G, to implement a DS0 granularity SBI Memory:Space:Memory switch scalable to 20 Gbit/s and NSE-8G, to implement a switch scalable to 8 Gbit/s. In TelecomBus mode, a 20 Gbit/s VT1.5/VT2 granularity Memory:Space:Memory switch can be implemented.
`Integrates two independent DS0 granularity Memory Switches. One switch is placed between the incoming 77.76 MHz byte-wide SBI336 bus and the transmit working and protect Serial SBI336S link. The transmit working and protect links transmit the same data. The other switch is placed between the receive working or protect Serial SBI336S link and the outgoing 77.76 MHz byte-wide SBI336 bus.
`Provides 125 nominal latency in DS0 mode. Channel Associated Signaling (CAS) latency through the SBSLITE in DS0 mode is two T1 multiframe (6 mS) or two E1 multiframe (4 mS).
`Provides less than 16 nominal latency in TelecomBus mode or SBI mode without DS0 level switching.
`Permits any receive or incoming byte from an input port to be mapped to any outgoing or transmit byte, respectively, on the associated output port through the Memory switch.
`Supports redundant working and protect serial SBI336S links in support of a redundant Memory:Space:Memory switch with the NSE.
`Encodes and decodes byte-wide SBI336 bus control signals for all SBI supported link types and clock modes for transport over the serial SBI336S interface.
`Encodes data from the Incoming SBI336 bus or TelecomBus stream to a working and protect 777.6 Mbit/s LVDS serial links with 8B/10B-based encoding.
`Decodes data from a working and protect 777.6 MHz low voltage differential serializer (LVDS) serial links with 8B/10B-based encoding to the Outgoing SBI336 bus or TelecomBus stream.
`In SBI mode, switches CAS bits with all DS0 data.

The PM8611 SBI336 Bus Serializer, SBSLITE, is a monolithic integrated circuit that implements conversion between a byte-serial 77.76 MHz SBI336 bus and redundant 777.6 Mbit/s bit-serial 8B/10B-base SBI336S bus. In TelecomBus mode, the SBSLITE implements conversion between a 77.76 MHz TelecomBus format and a redundant 777.6 Mbit/s bit-serial 8B/10B-base serial TelecomBus format. In line with the bus conversion is a DS0 granular switch allowing any input DS0 to be output on any output DS0.

The SBSLITE can be used to connect and switch high density T1/E1 framer devices supporting an SBI bus with link layer devices supporting an SBI bus over a serial backplane. Putting a Narrowband Switch Element (NSE) between the framer and link layer devices allows construction of up to 20 Gbit/s NxDS0 switches.

In the ingress direction, the SBSLITE connects an incoming 77.76 MHz SBI336 stream to a pair of redundant serial SBI336S LVDS links through a DS0 memory switch. In TelecomBus mode, an incoming 77.76 MHz TelecomBus that has the J1 path fixed and all high order pointer justifications converted to tributary pointer justifications can be switched through a VT granular switch to a pair of redundant serial LVDS TelecomBus format links. The incoming data is encoded into an extended set of 8B/10B characters and transferred onto two redundant 777.6 Mbit/s serial LVDS links. SBI or TelecomBus frame boundaries, pointer justification events and master timing controls are marked by 8B/10B control characters. Incoming synchronized payload envelopes (SPEs) may be optionally overwritten with the locally generated X23 + X18 + 1 PRBS pattern for diagnosis of downstream equipment. The PRBS processor is configurable to handle any combination of SPEs and can be inserted independently into either of the redundant LVDS links. A DS0 memory switch provides arbitrary mapping of streams on the incoming SBI336 bus stream to the working and protect LVDS links at DS0 granularity. In TelecomBus mode, a VT1.5/VT2 memory switch provides arbitrary mapping of tributaries on the incoming TelecomBus stream to the working and protect LVDS links. Multi-cast is supported.

In the egress direction, the SBSLITE connects two independent 777.6 Mbit/s serial LVDS links to an outgoing SBI336 Bus. Each link contains a constituent SBI336S stream. Bytes on the links are carried as 8B/10B characters. The SBSLITE decodes the characters into data and control signals for a single 77.76 MHz SBI336 bus. Alternatively the SBSLITE decodes two independent 777.6 Mbit/s TelecomBus formatted serial LVDS links characters into a single 77.76 MHz TelecomBus. A PRBS processor is provided to monitor the decoded payload for the X23 + X18 + 1 pattern in each SPE. The PRBS processor is configurable to handle any combination of synchronized payload envelopes (SPEs) in the serial LVDS link. Data on the outgoing SBI336 bus stream may be sourced from either of the LVDS links.

An In-band signaling link over the serial LVDS links allows this device to be controlled by a companion switching device, the Narrowband Switching Element, PM8620 NSE-20G. This link can be used as communication link between a central processor and the local microprocessor.