peb2035 ETC-unknow, peb2035 Datasheet - Page 66

• Manufacturer Part Number: peb2035
• Description: Communications Advanced Cmos Frame Aligner
• Manufacturer: ETC-unknow

Some of the above indications are only simulated if the ACFA is configured in a mode where the
alarm is applicable (e.g. no CRC4 error simulation when doubleframe format is enabled).
Controlling the alarm simulation depends on the selected PCM mode:
PCM 30 Mode
Setting of the bit CCR.SIM initiates alarm simulation. Error counting and indication will occurs while
this bit is set. After it is reset all simulated error conditions disappear. Alarms like AIS and NOS are
cleared automatically. The indications of slips, parity errors and the error counters have to be
cleared by setting/resetting corresponding bits of register CCR (CCR.CLR, CCR.CCPY).
PCM 24 Mde
The alarm simulation is controlled by the value of the Alarm Simulation Counter: ASR.SC which is
incremented by setting bit: CCR.SIM. Contrary to PCM 30 mode, resetting this bit has no influence
on running alarm simulation.
Clearing of alarm indications:
– automatically for NOS, remote alarm, AIS, and loss of synchronization and
– user controlled for slips, parity errors, and error counters via bit CCR.CLR
is only possible at defined counter steps of ASR.SC. For complete simulation (ASR.SC = 0), eight
simulation steps are necessary.
Speech Memory Supervision
During normal operation, the receive and transmit paths may be monitored to detect malfunctions
by using parity generation/checking and loopback of individual time-slots.
Parity Check
Both the receive and the transmit memories are supervised by a parity bit generation/checking
mechanism. A parity bit is generated at the input of the receive (resp. transmit) speech memory and
written to the memory along with the eight bit PCM data (in PCM 30 mode the transmit memory is
by-passed).
Parity is checked at the memory output and errors are reported via status bits:
Semiconductor Group
Framing error counter
Code violation counter (HDB3/B8ZS Codes)
CRC4/6 error counter
Receive Channel Parity Error: RSR.RPE (PCM 30), ASR.RPE (PCM 24) for the channel selected
via register CPY.
Transmit Channel Parity Error: RSP.XPE (PCM 30), ASR.XPE (PCM 24) for the channel
selected via register CPY.
Global Parity Error: RSP.GPE (PCM 30), MFR.GPE (PCM 24) for all transmit and receive
channels.
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PEB 2035