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MMC(SD)卡技术手册.pdf
MultiMediaCards
MMCA Seminar
Technical Presentation
Taipei, Sept. 2003
1
Contents
-MultiMediaCard Architecture
-MultiMediaCard Command
-MultiMediaCard Initialization
-MultiMediaCard Register
2
MultiMediaCard Architecture
3
System feature-1
- Multiple MultiMediaCard can be connected to one
physical bus.
30 pcs max.
- Variable clock frequency
0 to 20MHz
(up to 10 cards for max data rate)
- Transfer data size is changeable.
1 byte to 2,048 bytes ( for Read )
4
System feature-2
- System voltage range
High voltage MMC : 2.7-3.6v
Low voltage MMC : 1.65-1.95v, 2.7-3.6v
- Two form factors
Normal size : 24mm x 32mm x 1.4mm
Reduced size : 24mm x 18mm x 1.4mm
RS-MMC
RS-MMC adapter
MMC
5
System feature-3
Two operation mode
- MMC mode (Primary)
3 pins serial bus
- SPI mode (Secondary)
3 pins serial bus + Chip select pin
These 2 modes are independent in each.
After Card is powered on , card executes the initialization
procedure and the mode is set with the level of #1 pin at the
powered on. To change the mode another power cycle is
required.
6
Pin
description
7
6
5
4
3
2
1
MMC mode
Pin No.
1
2
3
4
5
6
7
Name
RSV
CMD
VSS1
VDD1
CLK
VSS2
DAT
Description
Reserved
Command/Response
GND
VCC
Clock
GND
Data in/out
SPI mode
Description
Chip select
Data in
GND
VCC
Clock
GND
Data out
Name
CS
DI
VSS
VDD
SCLK
VSS2
DO
After power on card is set as MMC mode as default.
7
Comparison table of MMC and SPI mode
SPI I/F
3 pins serial bus + CS
(CLK,DI,DO & CS)
0-20 MHz
Card is selected by the CS signal.
Single block access
Multi block access ( from Ver.3.1)
Name
Description
Type
Input
Input
Push-pull
Input
CS
DI
VSS
VDD
SCLK
VSS2
DO
Chip select
Data in
GND
VCC
Clock
GND
Output
Push-pull
Data out
Comparison
of system
specification
Pin
Arrangement
Interface
Frequency
Card
Selection
Access
mode
Pin No.
1
2
3
4
5
6
7
MMC I/F
3 pins serial bus
(CLK,CMD,DAT)
0-20 MHz
Card is selected by MMC bus protocol.
Host sends the relative card address
toselect the card which has the same one.
Single block access, Multiple block access
Stream access
Name
RSV
CMD
VSS1
VDD1
CLK
VSS2
DAT
Type
NC
I/O
Push-pull/
Open-drain
Input
I/O
Push-pull
Description
Reserved
Command/Response
GND
VCC
Clock
GND
Data in/out
8
