SWRU626 December 2025 CC3501E , CC3551E
Different types of responses are specific to SD cards. See the SD Memory Card Specifications or the SD Card Specification, Part A2, SD Host Controller Standard Specification for more details.
Table 20-8 shows how the SD responses are stored in the SD_RSPxx registers.
| Kind of Response | Response Field | Response Register |
|---|---|---|
| R1, R1b (normal response), R3, R4, R5, R5b, R6, R7 | RESP[39:8](1) | SD_RSP10[31:0] |
| R1b (Auto CMD12 response) | RESP[39:8](1) | SD_RSP76[31:0] |
| R2 | RESP[127:0](1) | SD_RSP76 [31:0] SD_RSP54[31:0] SD_RSP32[31:0] SD_RSP10[31:0] |
When the host controller modifies part of the SD_RSPxx registers, it preserves the unmodified bits.
The host controller stores the Auto CMD12 response in the SD_RSP76[31:0] register because the Host Controller may have a multiple block data DAT line transfer executing concurrently with a command. This allows the host controller to avoid overwriting the Auto CMD12 response with the command response stored in SD_RSP10 register and vice versa.