Transcript prashant_sdcard_05282013x

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