Hi All, I am going to use PIC microcontroller as SD card (SPI mode) controller by the SPI interface of the PIC. Does anyone knows what is the effective baud rate of SD in SPI mode? I means what is the actually data transfer rate after removing the protocol added data, I am intending to work with the SPI in 25Mhz. Thanks Aharon --------------------------------------- This message was sent using the comp.arch.embedded web interface on http://www.EmbeddedRelated.com
PIC Micro SPI to SD Card Interface
Started by ●December 2, 2009
Reply by ●December 2, 20092009-12-02
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ashpigel wrote:> Hi All, > I am going to use PIC microcontroller as SD card (SPI mode) controller by > the SPI interface of the PIC. Does anyone knows what is the effective baud > rate of SD in SPI mode? I means what is the actually data transfer rate > after removing the protocol added data, I am intending to work with the SPI > in 25Mhz.Depends on a few factors: - -> Are you using DMA? - -> Are you doing bulk transfers or block by block - -> How cheap the memory card is! I've had the pleasure of working with one that spend ages doing unknown wizardry while the system waited for data to be ready. Without the useless card I mentioned above I got 1.5 MByte / sec without any particular optimisations with a PIC18F4620. - -- Brendan Gillatt | GPG Key: 0xBF6A0D94 brendan {a} brendangillatt (dot) co (dot) uk http://www.brendangillatt.co.uk -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) iD8DBQFLFnZqHEhZ5Ws5poERAvR0AJ9bmca+0CtOGehaqN5sHZngsPx2GwCdF6lq qSmOoaEzlodFt7ogXdvnaoo= =ib6K -----END PGP SIGNATURE-----