Information

Table 49-37. Commands for MMC/SD/SDIO/CE-ATA cards (continued)
CMD INDEX Type Argument Resp Abbreviation Description
ACMD51
10
adtc [31:0] stuff bits R1 SEND_SCR Reads the SD Configuration
Register (SCR).
1. CMD3 differs for MMC and SD cards. For MMC cards, it is referred to as SET_RELATIVE_ADDR, with a response type of
R1. For SD cards, it is referred to as SEND_RELATIVE_ADDR, with a response type of R6 (with RCA inside).
2. CMD6 differs completely between high speed MMC cards and high speed SD cards. Command SWITCH_FUNC is for
high speed SD cards.
3. Command SWITCH is for high speed MMC cards as well as for CE-ATA cards over the MMC interface. The Index field can
contain any value from 0-255, but only values 0-191 are valid. If the Index value is in the 192-255 range the card does not
perform any modification and the SWITCH_ERROR status bit in the EXT_CSD register is set. The Access Bits are shown
in Table 49-38.
4. ACMDs shall be preceded with the APP_CMD command. (Commands listed are used for SD only, other SD commands
not listed are not supported on this module).
5. ACMDs shall be preceded with the APP_CMD command. (Commands listed are used for SD only, other SD commands
not listed are not supported on this module).
6. ACMDs shall be preceded with the APP_CMD command. (Commands listed are used for SD only, other SD commands
not listed are not supported on this module).
7. ACMDs shall be preceded with the APP_CMD command. (Commands listed are used for SD only, other SD commands
not listed are not supported on this module).
8. ACMDs shall be preceded with the APP_CMD command. (Commands listed are used for SD only, other SD commands
not listed are not supported on this module).
9. ACMDs shall be preceded with the APP_CMD command. (Commands listed are used for SD only, other SD commands
not listed are not supported on this module).
10. ACMDs shall be preceded with the APP_CMD command. (Commands listed are used for SD only, other SD commands
not listed are not supported on this module).
The Access Bits for the EXT_CSD Access Modes are shown in the following table.
Table 49-38. EXT_CSD Access Modes
Bits Access Name Operation
00 Command Set The command set is changed according to the Cmd Set field of the argument
01 Set Bits The bits in the pointed byte are set, according to the 1 bits in the Value field.
10 Clear Bits The bits in the pointed byte are cleared, according to the 1 bits in the Value field.
11 Write Byte The Value field is written into the pointed byte.
49.7 Software restrictions
Software for the SDHC must observe the following restrictions.
Chapter 49 Secured digital host controller (SDHC)
K20 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc. 1481