RM0090: Reference manual - STMicroelectronics

Secure digital input/output interface (SDIO) RM0090
Table 138. AU_SIZE field (continued)
The maximum AU size, which depends on the card capacity, is defined in Table 139. 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.
ERASE_TIMEOUT
AU_SIZE Value definition
09h 4 MB
Ah – Fh Reserved
Table 139. 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 140. Erase size field
ERASE_SIZE Value definition
0000h Erase timeout calculation is not supported.
0001h 1 AU
0002h 2 AU
0003h 3 AU
--------- ---------
FFFFh 65535 AU
This 6-bit field indicates TERASE and the value indicates the erase timeout from offset when
multiple AUs are being erased as specified by ERASE_SIZE. The range of
ERASE_TIMEOUT can be defined as up to 63 seconds and the card manufacturer can
choose any combination of ERASE_SIZE and ERASE_TIMEOUT depending on the
implementation. Determining ERASE_TIMEOUT determines the ERASE_SIZE.
Table 141. Erase timeout field
ERASE_TIMEOUT Value definition
00 Erase timeout calculation is not supported.
01 1 [sec]
02 2 [sec]
03 3 [sec]
871/1416 Doc ID 018909 Rev 3