CN8478/CN8474A/CN8472A/CN8471A
6.0 Basic Operation
Multichannel Synchronous Communications Controller (MUSYCC™)
6.4 Protocol Support
SS7 Signal Unit Error Rate
(SUERR) Interrupt
In the case of an SS7 SUERR, an error is detected in SS7 mode which caused a
counter for SS7 related errors to equal or exceed the permitted threshold value.
The threshold is stored on a per-channel group basis in the bit field SUET in a
Group Configuration Descriptor.
Reasons:
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A Short SS7 message increments the SS7 counter.
An FCS error in the SS7 message increments the SS7 counter.
An Octet alignment error in the SS7 message.
Accumulation of 16 “octet count” type errors increments counter.
NOTE: Receiving 256 unerrored SS7 messages decrements the SS7counter.
Effects:
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The Interrupt Descriptor in Interrupt Queue with ERROR = SUERR,
DIR = 0 (if MSKSUERR = 0 in Receive Channel Configuration
Descriptor).
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The BLP scans for the opening flag of the next HDLC message.
Simultaneously, DMAC checks for Message Descriptor ownership before
transferring received data to shared memory.
Channel Level Recovery Actions:
None required.
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6.4.9 Transparent Mode
MUSYCC supports a transparent mode where no distinction is made between
information and non-information bits in the data bit stream. This mode is
assigned on a per channel and direction basis by the bit field PROTOCOL in the
Channel Configuration Descriptor.
In transparent mode, the following characteristics apply:
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All data bits are transferred between shared memory and the serial
interface without protocol support such as those listed for the HDLC
mode.
Host must maintain the necessary data transfer rates at all times by
providing Message Descriptors and data buffers for both the transmit and
receive channels.
The host must always set the bit field EOM to 0 in each Transmit Buffer
Descriptor. Setting EOM to 1 causes indeterminate results. Due to
EOM = 0, the other Transmit Buffer Descriptor bit fields—IC, PADEN,
PADCNT, and REPEAT—are ineffective.
Unlike HDLC mode, MUSYCC does not poll a host-owned Transmit Buffer
Descriptor during transparent mode.
When the internal buffer is empty and no more transmit data is available from
shared memory (i.e., host-owned buffer), MUSYCC does the following:
1. Issues an ONR error.
2. Enters the channel deactivate state, sending idle code on the affected
channel.
100660E
Conexant
6-43
CONEXANT [ CONEXANT SYSTEMS, INC ]
