Rainbow Electronics DS3131 - Manual (Page 53)

DS3131
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Register Name:
BERTC0
Register Description:
BERT Control Register 0
Register Address:
0500h
Bit # 7 6 5 4 3 2 1 0
Name reserved TINV RINV PS2 PS1 PS0 LC RESYNC
Default 0 0 0 0 0 0 0 0
Bit # 15 14 13 12 11 10 9 8
Name IESYNC IEBED IEOF reserved RPL3 RPL2 RPL1 RPL0
Default 0 0 0 0 0 0 0 0
Note: Bits that are underlined are read-only; all other bits are read-write.
Bit 0/Force Resynchronization (RESYNC). A low-to-high transition forces the receive BERT synchronizer to
resynchronize to the incoming data stream. This bit should be toggled from low to high whenever the host wishes
to acquire synchronization on a new pattern. It must be cleared and set again for a subsequent resynchronization.
Note: Pattern selects bits PS0~2 must be set before resync.
Bit 1/Load Bit and Error Counters (LC). A low-to-high transition latches the current bit and error counts into
the host accessible registers BERTBC and BERTEC and clears the internal count. This bit should be toggled from
low to high whenever the host wishes to begin a new acquisition period. Must be cleared and set again for
subsequent loads.
Bit 2/Pattern Select Bit 0 (PS0); Bit 3/Pattern Select Bit 1 (PS1); Bit 4/Pattern Select Bit 2 (PS2)
000 = pseudorandom pattern 2E7 - 1
001 = pseudorandom pattern 2E11 - 1
010 = pseudorandom pattern 2E15 - 1
011 = pseudorandom pattern QRSS (2E20 - 1 with a 1 forced, if the next 14 positions are 0)
100 = repetitive pattern
101 = alternating word pattern
110 = illegal state
111 = illegal state
Bit 5/Receive Invert Data Enable (RINV)
0 = do not invert the incoming data stream
1 = invert the incoming data stream
Bit 6/Transmit Invert Data Enable (TINV)
0 = do not invert the outgoing data stream
1 = invert the outgoing data stream
Bit 8/Repetitive Pattern Length Bit 0 (RPL0); Bit 9/Repetitive Pattern Length Bit 1 (RPL1);
Bit 10/Repetitive Pattern Length Bit 2 (RPL2); Bit 11/Repetitive Pattern Length Bit 3 (RPL3). RPL0 is the
LSB and RPL3 is the MSB of a nibble that describes the how long the repetitive pattern is. The valid range is 17
(0000) to 32 (1111). These bits are ignored if the receive BERT is programmed for a pseudorandom pattern. To
create repetitive patterns less than 17 bits in length, the user must set the length to an integer number of the desired
length that is less than or equal to 32. For example, to create a 6-bit pattern, the user can set the length to 18 (0001)
or to 24 (0111) or to 30 (1101).