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PEB 20550
PEF 20550
Functional Description
Semiconductor Group
52
01.96
2.2.6.5 Special Functions
– Synchronous transfer.
This utility allows the synchronous
μ
P-access to two independent channels on the
PCM- or CFI-interface. Interrupts are generated to indicate the appropriate access
windows.
– 7-bit hardware timer.
The timer can be used to cyclically interrupt the CPU, to determine the double last look
period, to generate a proper CFI-multiframe synchronization signal or to generate a
defined RESIN pulse width.
– Frame length checking.
The PFS-period is internally checked against the programmed frame length.
– Alternative input functions.
In PCM-mode 1 and 2, the unused ports can be used for redundancy purposes. In
these modes, for every active input port a second input port exists which can be
connected to a redundant PCM-line. Additionally the two lines are checked for
mismatches.
2.2.7
The SACCO (Special Application Communication Controller) is a high level serial
communication controller consisting of two independent HDLC-channels (A + B). It is a
derivative product of the Siemens SAB 82525 (HSCX).
The SACCO essentially reduces the hardware and software overhead for serial
synchronous communication. SACCO channel A can be multiplexed by the D-channel
arbiter to serve multiple subscribers.
In the following section one SACCO channel is described referring to as "SACCO".
SACCO
2.2.7.1 Block Diagram
The SACCO (one channel) provides two independent 64-byte FIFOs for receive and
transmit direction and a sophisticated protocol support. It is optimized for line card
applications in digital exchange systems and offers special features to support:
– Communication between a line card and a group controller
– Communication between terminal equipment and a line card