Wearwulf

The Mass Storage Interface

Multimedia Cards (MMCs) are well suited for embedded applications because they are small, low-power, and connect with the minimum of signal pins. The MMC can communicate with a processor using either the MMC standard protocol, or a SPI bus - the LPC2106 has a built-in SPI bus interface.

The protocol to communicate with the MCC card is clearly outlined in »an acrobat document by Hitachi. Layered on top of this will be the need to read and write in a format that can be accessed by desktop readers in PCs.

The LPC2106's SSEL pin selects the LPC2106 when it used as an SPI slave. Two general purpose pins will be provided to act as chip selects for the MMC and Geek Port interfaces as appropriate. Any remaining free GPIO pins will be made available for addiitonal chip selects for extra SPI-based devices.