1 bert repetitive pattern set, 2 bert error counter, Bert repetitive pattern set – Rainbow Electronics DS26519 User Manual
Page 107: Bert error counter
DS26519 16-Port T1/E1/J1 Transceiver
107 of 310
The BERT block can generate and detect the following patterns:
• The pseudorandom patterns 2E7-1, 2E9-1, 2E11-1, 2E15-1, and QRSS.
• A repetitive pattern from 1 to 32 bits in length.
• Alternating (16-bit) words that flip every 1 to 256 words.
• Daly pattern.
The BERT function must be enabled and configured in the
registers for each port. The BERT can
then be assigned on a per-channel basis for both the transmitter and receiver, using the special per-channel
function in the
-4 and
-4 registers. Individual bit positions within the channels can be suppressed
registers. Using combinations of these functions, the BERT pattern can be transmitted
and/or received in single or across multiple DS0s, contiguous or broken. Transmit and receive bandwidth
assignments are independent of each other.
The BERT receiver has a 32-bit bit counter and a 24-bit error counter. The BERT receiver can generate interrupts
on: a change in receive-synchronizer status, receive all zeros, receive all ones, error counter overflow, bit counter
overflow, and bit error detection. Interrupts from each of these events can be masked within the BERT function via
the BERT Status Interrupt Mask Register (
). If the software detects that the BERT has reported an event, then
the software must read the BERT Latched Status Register (
) to determine which event(s) has occurred.
9.13.1 BERT Repetitive Pattern Set
These registers must be properly loaded for the BERT to generate and synchronize to a repetitive pattern, a
pseudorandom pattern, alternating word pattern, or a Daly pattern. For a repetitive pattern that is fewer than 32
bits, the pattern should be repeated so that all 32 bits are used to describe the pattern. For example, if the pattern
was the repeating 5-bit pattern …01101… (where the rightmost bit is the one sent first and received first), then
BRP1 should be loaded with ADh, BRP2 with B5h, BRP3 with D6h, and BRP4 should be loaded with 5Ah. For a
pseudorandom pattern, all four registers should be loaded with all ones (i.e., FFh). For an alternating word pattern,
one word should be placed into BRP1 and BRP2 and the other word should be placed into BRP3 and BRP4. For
example, if the DDS stress pattern “7E” is to be described, the user would place 00h in BRP1, 00h in BRP2, 7Eh in
BRP3, and 7Eh in BRP4, and the alternating word counter would be set to 50 (decimal) to allow 100 bytes of 00h
followed by 100 bytes of 7Eh to be sent and received.
9.13.2 BERT Error Counter
Once BERT has achieved synchronization, this 24-bit counter will increment for each data bit received in error.
Toggling the LC control bit in BC1 can clear this counter. This counter saturates when full and will set the BECO
status bit in the
register.