Arria® V Device Handbook: Volume 2: Transceivers

ID 683573
Date 5/29/2020
Document Table of Contents Bit Reversal

You can reverse the bit order at the output of the word aligner for receiving a MSB-to-LSB transmission using the bit reversal feature at the receiver.
Table 29.  Bit Reversal Feature
Transmission Bit Order
Bit Reversal Option 8- or 10-bit Serialization Factor 16- or 20-bit Serialization Factor
Disabled (default) LSB to MSB LSB to MSB
Enabled MSB to LSB

For example:

8-bit—D[7:0] rewired to D[0:7]

10-bit—D[9:0] rewired to D[0:9]


For example:

16-bit—D[15:0] rewired to D[0:15]

20-bit—D[19:0] rewired to D[0:19]

Note: When receiving the MSB-to-LSB transmission, the word aligner receives the data in reverse order. The word alignment pattern must be reversed accordingly to match the MSB-first incoming data ordering.

You can dynamically control the bit reversal feature using the rx_bitreversal_enable register with the word aligner in bit-slip mode. When you dynamically enable the bit reversal feature in bit-slip mode, you can ignore the pattern detection function in the word aligner because the word alignment pattern cannot be dynamically reversed to match the MSB-first incoming data ordering.