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, , . , , , , - , .
, EEPROM USB USB ( , ). , - , , SD . , (, , , ). , , . .
Secure Digital (SD)
SD .
Secure Digital (, ) flash , , . , , flash (Memory Core) , , 8 . , (, , ), , , , (, , , 80 ).
SD Panasonic, SanDisk Toshiba MMC . SD Card Association, SD. , , , , Physical Layer Simplified Specification (Copyright 2001-2006 SD Group (Panasonic, SanDisk, Toshiba) and SD Card Association). , , 2000 . R&D . , , , . , , :
SD ( SDSC (Secure Digital Standard Capacity)) . 2 . 1 .
SDHC (Secure Digital High Capacity) ( 32 ). , , 512 . , , , 71 : , , 512 . , , , - 32- - , , . SDHC , .
SDXC (Secure Digital eXtended Capacity) 2T . 512 . 32- : (2^32)*512 = 2 .
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, . Physical Layer Simplified Specification , . , / . , mini-, microSD, microSDXC .. .
: , , , , , Security Digital . , , , . SD, SDHC . , , : SD UHS-II ( ) , SPI.
, Security Digital : SD, UHS-II SPI. , , , , . SPI , ( ), , . , . , , , SPI , SD . , SD , ? Stm32f4 STMicroelectronics, SDIO (Security Digital Input Output), , .
SD ? :
, ;
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. ( , ..), , , ( );
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, , ( ).
Pin 4 ;
Pin 3, 6 ;
Pin 5 ;
Pin 2 ;
Pin 1, 7, 8, 9 4- .
, , CLK. , . , ( ) . 1- ( D0) 4- . , SD Push-Pull 4.5 10 . .
, !
.
1) .
.
, () , . , , , . , , . , :
48 . . , , . , , . 7- , (CRC) . : CMD ( ) ACMD (Application-Specific Command). , . 80 ( , ) . , (, , ). , CMD ACMD. 6 32 , .
ACMD: CMD , , , Application-Specific, CMD55!
( ) , , .
R1 (normal response command) 48 . , .
, ( ), 6 , , , , . 32 . , ( /, /, , ).
R1b , R1 , (busy) .
R2 (CID, CSD register) 136 CID CSD .
127 , CID ( , CMD2 CMD10 ), CSD ( CMD9 ). , , ?
CID (Card identification data) , ( , , ). CSD (Card-specific data) ( , /, , ). .
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R3 48 , ACMD41 OCR (Operation Conditions Register) .
ACMD41 . , OCR ( , , ).
R6 (Published RCA response) RCA (Relative card address) .
. , . RCA .
R7 (Card interface condition) 48 CMD8.
, . ( ). ( , ) ( ).
2) .
( ), . , , , . , 512 ( SDHC ) 512 . , , - . , 1- 4- . ().
: (block read operation) (multiple block read operation). , , , .
() , busy, ( ).