SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The VCPs can be configured to generate either hard decisions (one bit per decision), or soft decisions (8-bit value per decision). Ordering of the VCP decisions depends on the VCP_VCPIC3[28] OUT_ORDER bit-field and the VCP_VCPEND[1] SD bit, if the DSP is set to work in big-endian mode and the results or Soft Decisions (see the VCP version 2 endian mode register VCP_VCPEND). The decisions buffer start address must be double-word aligned and the buffer size must be a multiple of 8 bytes.
The soft decisions in the VCP are initially computed with the path metrics at 13-bit values. The results are then clipped to 8-bit signed integer values before being stored in the traceback soft decision memory.