SanDisk SD064 Manual descarregar pdf (Página 31)

3$ CARDS SUPPORT hHOTv INSERTION OF THE CARD IE THE CARD CAN BE INSERTED INTO THE CIRCUIT

WITHOUT POWERING DOWN THE HOST 4HIS IS USUALLY ACHIEVED THROUGH THE CARD CONNECTOR

#ONNECTOR MANUFACTURERS USUALLY PROVIDE SOCKETS THAT HAVE POWER PINS LONG ENOUGH TO POWER

THE CARD BEFORE ANY CONTACT IS MADE WITH THE OTHER PINS

! FEATURE OF MOST 3$ CARDS IS THE AUTOMATIC ENTRY AND EXIT FROM SLEEP MODE !FTER AN

OPERATION CARDS USUALLY ENTER A SLEEP MODE TO CONSERVE POWERIN IF NO MORE COMMANDS ARE

RECEIVED WITHIN  MS !LTHOUGH THE HOST DOES NOT NEED TO DO ANYTHING FOR THIS TO HAPPEN IT

IS RECOMMENDED THAT THE HOST SHUT THE CLOCK GENERATION !NY COMMAND SENT TO THE CARD WILL

FORCE IT TO EXIT FROM THE SLEEP MODE

3$ CARDS CAN CONSUME UP TO n M! WHILE READING OR WRITING ONTO THE CARD 4HIS

IS USUALLY A HIGH CURRENT AND AN APPROPRIATE VOLTAGE REGULATOR CAPABLE OF SUPPLYING THE

REQUIRED CURRENT MUST BE USED IN THE DESIGN 4HE CARD CONSUMES APPROXIMATELY  MA in

SLEEP MODE

3.13 SD Card Internal Registers

4HE OPERATIONS OF 3$ CARDS ARE CONTROLLED BY A NUMBER OF INTERNAL REGISTERS 3OME REGISTERS

ARE  BITS WIDE SOME ARE  BITS WIDE AND SOME ARE  BITS WIDE 4ABLE  GIVES A LIST OF

ALL THE REGISTERS

$ETAILED INFORMATION ON THE FUNCTIONS AND BIT DElNITIONS OF ALL THE REGISTERS CAN BE FOUND

IN THE PRODUCT MANUALS OF CARD MANUFACTURERS EG SanDisk Secure Digital Card, Product

Manual, Document no: 80-13-00169, 2003 4HE DETAILS OF THE IMPORTANT REGISTERS AND THEIR

BIT DElNITIONS ARE GIVEN IN THIS SECTION

Figure 3.14: PIC Microcontroller SD Card Interface

PIC

3,6

3.3K

2.2K

3.3 K

2.2K

RC2

RC3

RC4

RC5

SD card

3.6 V 2.48 V

CLK

122 Chapter 3

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SanDisk SD064 Manual Página 31