7 pin MM-card special connector at the card
The MultiMedia Card communication is based on serial bus designed to operate in a low voltage range. For compatibility to existing controllers the cards may offer,in addition to the MultiMedia Card mode, an alternate communication protocol which is based on the SPI standard.
|1||RSV NC||Not connected or Always “1” (data 3?)|
|3||VSS1 S||Supply Voltage Ground|
|4||VDD S||Supply Voltage|
|6||VSS2 S||Supply Voltage Ground|
|7||DAT0 I/O||PP Data 0|
- CLK - with each cycle of this signal an one bit transfer on the command and data lines is done. The frequency may vary between 0-20MHz.
- CMD - is a bidirectional command channel used for card initialization and data transfer commands.
- DAT - is a bidirectional data channel. The DAT signal operates in push-pull mode. Only one card or the host is driving this signal at a time.