MICRO SD CARD INTERFACING WITH MSP430

HARDWARE USED

• Transcend micro SDHC 4 4 GB CARD.• Sandisk micro SD adapter.• Few pull-up resistors to avoid floating values

on pins.• MSP430 controller.

AUTOMATIC DETECTION It can be acheived by 2 ways-• By using extra pin as interupt with VCC provided through pull up

resistor which will be sorted to ground of micro SD card .• Through software routines at differnt interval(may be 2-3 sec). Some random commands will be given through MOSI(master

output slave input) pin and output will be recorded. If output at both time is either 00..0 or FF...F or same for both

trial then we can conclude that there’s no card inserted else card is present and we will move for initialization process.

MODES OF OPERATION SD/SPI• SD mode is basically 4 line data transfer mode with a single

command line and cyclic redundancy check (CRC).• SPI mode with separate data line for input and output. Fortunately , MSP430 have dedicated hardware for SPI mode

so SPI communication require less software routines as compared to SD mode and even no worry about CRC which consumes extra time.

• SPI mode is 2 types – 3 pin (for single master system) 4 pin (for multiple master system) we have single master so will use 3 pin SPI mode.

MULTIPLE SD CARD INTERFACE

• MSP430 have 2 embeded slots for SPI communication.

• Even we can at a time interface with more than 2 cards by having chip select pin.

• Even other data transfer modules can be converted to SPI mode ex- Bluetooth modules ,USB based Flash devices at a time.

THANK YOU

PRASHANT PANDEY