SD Card

Speeds

SD Card standard speeds

SDHC

• SDHC cards are physically and electrically identical to standard-capacity SD cards (SDSC). The major compatibility issues between SDHC and SDSC cards are the redefinition of the Card-Specific Data (CSD) register in Version 2.0 (see below), and the fact that SDHC cards are shipped preformatted with the FAT32 file system.

SD Card Standards information

• Simplified specification is free to public.
• No host licence required if using only SPI mode
• SD Card Max Clock Rate = 208MHz (SD, miniSD, microSD) but only in SD Bus mode (not SPI mode).
• Max SPI transfer speed:
  • SD = 25Mbits/sec or 25MHz clock speed. (2.98MB/sec). 24MHz = 2.86MB/sec
  • miniSD/microSD = 50MBits/sec or 50MHz clock speed. (5.96MB/sec). 48MHz = 5.72MB/sec
• Latest SD Card Simplified Specifications (PDF)

• Pinout information on pg11 of part1_410.pdf.

• Information on calculating CRCs (TXT), (HTML)

SD Card Modules

• £1, only supports SPI Mode: http://www.ebay.co.uk/itm/New-Perfect-SD-Card-Module-Slot-Socket-Reader-For-Arduino-ARM-MCU-Read-And-Write-/200931314518?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item2ec8708b56

Existing Code/Libraries

• NXP Application Note AN11070 (ZIP)
• NXP Application Note AN10916 (ZIP)

http://www.nxp.com/products/microcontrollers/cortex_m3/LPC1768FBD100.html#documentation

[AN11070_PDF]: