SWRU626 December 2025 CC3501E , CC3551E
A margin named Ncrc in range of 2 to 8 cycles has been defined for SDR50 and SDR104 card components for write data transfers, as auto command 12 'end bit' shall arrive after the CRC status "end bit".
Figure 20-18 shows auto CMD12 timings during write transfer.
Figure 20-18 Auto CMD12 Timing During Write
TransferThe Host controller has a margin of 18 clock cycles to make sure that auto CMD12 'end bit' arrives after the CRC status. This margin does not depend on SDMMC bus configuration, 1 or 4 bus width.