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©Copyright 2000-2007 SD Card Association
SDIO Simplified Specification Version 2.00
7
ACMD41 Arg=0
Check Response
Set New Voltage (if needed)
ACMD41 Arg=HCS, WV
Check Response
A
OCR valid
MRDY=0
1sec Timeout
Unusable card
(Inactive State)
MRDY=1
Test MEM Flag
Skip memory initialize or MEM=1
Execute memory initialize & MEM=0
B
MEM=1
CMD2
CMD3
Test Flags
Not SD
Card
Unusable card
(Inactive State)
CMD15 RCA=0
OCR invalid
Test IO Flag
IO=1
IO=0
IO=0, MEM=1
IO=1,
MEM=1
IO=1, MEM=0
No Response
No Response
High Capacity Support Host: HCS=1
Memory Initialized
If F8=1, CCS is valid
Get memory OCR
IO Only
Card
Standard
Capacity
Memory
Only Card
High
Capacity
Memory
Only Card
Standard
Capacity
Combo
Card
High
Capacity
Combo
Card
Test CCS
Test CCS
CCS=0
CCS=1
CCS=0
CCS=1
ACMD41 Arg=0
Check Response
Set New Voltage (if needed)
ACMD41 Arg=HCS, WV
Check Response
A
OCR valid
MRDY=0
1sec Timeout
Unusable card
(Inactive State)
MRDY=1
Test MEM Flag
Skip memory initialize or MEM=1
Execute memory initialize & MEM=0
B
MEM=1
CMD2
CMD3
Test Flags
Not SD
Card
Unusable card
(Inactive State)
CMD15 RCA=0
OCR invalid
Test IO Flag
IO=1
IO=0
IO=0, MEM=1
IO=1,
MEM=1
IO=1, MEM=0
No Response
No Response
High Capacity Support Host: HCS=1
Memory Initialized
If F8=1, CCS is valid
Get memory OCR
IO Only
Card
Standard
Capacity
Memory
Only Card
High
Capacity
Memory
Only Card
Standard
Capacity
Combo
Card
High
Capacity
Combo
Card
Test CCS
Test CCS
CCS=0
CCS=1
CCS=0
CCS=1
Variables
NF:
Number of I/O Functions (CMD5 Response)
MP: Memory
Present
Flag (CMD5 Response)
IORDY: I/O Power-up Status (C bit in the CMD5 response)
MRDY:
Memory Power-up Status (OCR Bit31)
HCS:
Host Capacity Support (ACMD41 Argument)
CCS:
Card Capacity Status (ACMD41 Response)
Flags
IO:
I/O Functions Initialized Flag
MEM:
Memory Initialized Flag
F8: CMD8
Flag
Figure 3-2 Card initialization flow in SD mode (SDIO aware host)