48.10.2 SDMMC Block Size Register
| Name: | SDMMC_BSR |
| Offset: | 0x04 |
| Reset: | 0x0000 |
| Property: | Read/Write |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| BOUNDARY[2:0] | BLKSIZE[9:8] | ||||||||
| Access | R/W | R/W | R/W | R/W | R/W | ||||
| Reset | 0 | 0 | 0 | 0 | 0 | ||||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| BLKSIZE[7:0] | |||||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
Bits 14:12 – BOUNDARY[2:0] SDMA Buffer Boundary
Specifies the size of the contiguous buffer in the system memory. The SDMA transfer waits at every boundary specified by this field and the SDMMC generates the DMA Interrupt to instruct the software to update SDMMC_SSAR. If this field is set to 0 (buffer size = 4 Kbytes), the lowest 12 bits of SDMMC_SSAR.ADDRESS point to data in the contiguous buffer, and the upper 20 bits point to the location of the buffer in the system memory. This function is active when SDMMC_TMR.DMAEN is set.
| Value | Name | Description |
|---|---|---|
| 0 | 4K | 4-Kbyte boundary |
| 1 | 8K | 8-Kbyte boundary |
| 2 | 16K | 16-Kbyte boundary |
| 3 | 32K | 32-Kbyte boundary |
| 4 | 64K | 64-Kbyte boundary |
| 5 | 128K | 128-Kbyte boundary |
| 6 | 256k | 256-Kbyte boundary |
| 7 | 512K | 512-Kbyte boundary |
Bits 9:0 – BLKSIZE[9:0] Transfer Block Size
Specifies the block size of data transfers for CMD14, CMD17, CMD18, CMD19, CMD24, CMD25, CMD53 and other data transfer commands such as CMD6, CMD8, ACMD13 and ACMD51. Values ranging from 1 to 512 can be set. It can be accessed only if no transaction is executing (i.e., after a transaction has stopped). Read operations during transfers may return an invalid value, and write operations are ignored.