mt9074ap1 Zarlink Semiconductor, mt9074ap1 Datasheet - Page 54

• Manufacturer Part Number: mt9074ap1
• Description: T1/e1/j1 Single Chip Transceiver With Wide Dynamic Range Liu
• Manufacturer: Zarlink Semiconductor

MT9074
Data Sheet
Bipolar Violation Error Counter (BPV15-BPV0)
The bipolar violation error counter will count bipolar violations or encoding errors that are not part of HDB3
encoding in E1 mode. This counter BPV15-BPV0 is 16 bits long (page 4H, addresses 16H and 17H) and is
incremented once for every BPV error received. It should be noted that when presetting or clearing the BPV error
counter, the least significant BPV counter address should be written to before the most significant location.
In E1 mode, there are two maskable interrupts associated with the bipolar violation error measurement. BPVI (page
01H, address 1CH) is initiated when the l significant bit of the BPV error counter toggles. BPVO (page 01H, address
1DH) is initiated when the counter changes from FFFFH to 0000H.
CRC-4 Error Counter (CC9-0)
CRC-4 errors are counted by the MT9074 in order to support compliance with ITU-T requirements. This ten bit
counter is located on page 04H, addresses 18H and 19H in E1 mode. It is incremented by single error events,
which is a maximum rate of twice per CRC-4 multiframe.
There is a maskable interrupt associated with the CRC error measurement. CRCIM (page 01H, address 1CH) is
initiated when the least significant bit of the counter toggles, and CRCOM (page 01H, address 1DH) is initiated
when the counter overflows.
PRBS Error Counter (PS7-0)
There are two 8 bit counters associated with PRBS comparison; one for errors and one for time. Any errors that are
detected in the receive PRBS will increment the PRBS Error Rate Counter of page 04H, address 10H. Writes to this
counter will clear an 8 bit counter, PSM7-0 (page 04H, address 11H) which counts receive CRC multiframes. A
maskable PRBS counter overflow (PRBSO) interrupt (page 1, address 1DH) is associated with this counter.
CRC Multiframe Counter for PRBS (PSM7-0)
This eight bit counter counts receive CRC-4 multiframes. It can be directly loaded via the microport. The counter will
also be automatically cleared in the event that the PRBS error counter is written to by the microport. This counter is
located on page 04H, address 11H.
Error Insertion
In T1 mode, MT9074 has six types of error conditions can be inserted into the transmit DS1 data stream through
control bits, which are located on page 1, address 19H - Error Insertion Word. These error events include the
bipolar violation errors (BPVE), CRC-6 errors (CRCE), Ft errors (FTE), Fs errors (FSE), payload (PERR) and a loss
of signal condition (LOSE). The LOSE function overrides the B8ZS encoding function.
In E1 mode, MT9074 has six types of error conditions can be inserted into the transmit PCM30 data stream through
control bits, which are located on page 01H, address 19H. These error events include the bipolar violation errors
(BPVE), CRC-4 errors (CRCE), FAS errors (FASE), NFAS errors (NFSE), payload (PERR) and a loss of signal error
(LOSE). The LOSE function overrides the HDB3 encoding function.
Per Time Slot Control Words
There are two per time slot control pages (addresses AH and BH) (T1/E1) occupying a total of 24 unique addresses
in T1 mode or a total of 32 unique addresses in E1 mode. Each address controls a matching timeslot on the 24 DS1
channels (T1) or 32 PCM-30 channels (E1) and the equivalent channel data on the receive (DSTo) data. For
example address 0 of the first per time slot control page contains program control for transmit timeslot 0 and DSTo
channel 0.
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