DocID024597 Rev 3 1423/1693
RM0351 SD/SDIO/MMC card host interface (SDMMC)
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AU_SIZE
This 4-bit field indicates the AU size and the value can be selected in the power of 2 base
from 16 KB.
The maximum AU size, which depends on the card capacity, is defined in Table 233. The
card can be set to any AU size between RU size and maximum AU size.
ERASE_SIZE
This 16-bit field indicates NERASE. When NERASE numbers of AUs are erased, the timeout
value is specified by ERASE_TIMEOUT (Refer to ERASE_TIMEOUT). The host should
determine the proper number of AUs to be erased in one operation so that the host can
show the progress of the erase operation. If this field is set to 0, the erase timeout
calculation is not supported.
02h 02h 2 [MB/sec]
--------- ---------
FEh 254 [MB/sec]
FFh Infinity
Table 232. AU_SIZE field
AU_SIZE Value definition
00h Not defined
01h 16 KB
02h 32 KB
03h 64 KB
04h 128 KB
05h 256 KB
06h 512 KB
07h 1 MB
08h 2 MB
09h 4 MB
Ah – Fh Reserved
Table 233. Maximum AU size
Capacity 16 MB-64 MB 128 MB-256 MB 512 MB 1 GB-32 GB
Maximum AU Size 512 KB 1 MB 2 MB 4 MB
Table 231. Performance move field (continued)
PERFORMANCE_MOVE Value definition