Table 230. Speed Class Code Field; Table 231. Performance Move Field - ST STM32L4x6 Reference Manual

SD/SDIO/MMC card host interface (SDMMC)
Bits Identifier
407:402 ERASE_TIMEOUT S R
401:400 ERASE_OFFSET
399:312 Reserved
311:0 Reserved for Manufacturer
SIZE_OF_PROTECTED_AREA
Setting this field differs between standard- and high-capacity cards. In the case of a
standard-capacity card, the capacity of protected area is calculated as follows:
Protected area = SIZE_OF_PROTECTED_AREA_* MULT * BLOCK_LEN.
SIZE_OF_PROTECTED_AREA is specified by the unit in MULT*BLOCK_LEN.
In the case of a high-capacity card, the capacity of protected area is specified in this field:
Protected area = SIZE_OF_PROTECTED_AREA
SIZE_OF_PROTECTED_AREA is specified by the unit in bytes.
SPEED_CLASS
This 8-bit field indicates the speed class and the value can be calculated by P
P is the write performance).
W
00h
01h
02h
03h
04h – FFh
PERFORMANCE_MOVE
This 8-bit field indicates Pm (performance move) and the value can be set by 1 [MB/sec]
steps. If the card does not move used RUs (recording units), Pm should be considered as
infinity. Setting the field to FFh means infinity.
PERFORMANCE_MOVE
00h
01h
1422/1693
Table 229. SD status (continued)
Type
Timeout value for erasing areas
specified by
UNIT_OF_ERASE_AU
Fixed offset value added to erase
S R
time.

Table 230. Speed class code field

SPEED_CLASS

Table 231. Performance move field

DocID024597 Rev 3
Value
(See below)
(See below)
Value definition
Class 0
Class 2
Class 4
Class 6
Reserved
Not defined
1 [MB/sec]
Description
W
Value definition
RM0351
Clear
condition
A
A
/2 (where