I am going to use MMC/SD card in my project ( MCU=AVR ) but i am little confused in these memories , in speed part ...
i need something about 400KB Reading speed from card in multiple block reading ( continues ) but somewhere i have seen Read speed is less than what i want , for example in this link :
http://elm-chan.org/fsw/ff/img/rwtest.png
but here it is said that speed is up to 5MB/s Read speed :
**broken link removed**
is that much difference usual ?
and if kingston is true , 5 MB/s means 40 Mb/s , but the maximum speed for SD is 25 MHz in SD_specs ... , it means it is not achievable in SPI mode ? and we should use SD 4bit bus mode ?
i am going to use SPI mode for both MMC & SD .
somewhere it is said ( in datasheets ) data transfer rate is up to 20 Mb/s,
is data transfer rate different by data writing and reading rate ???
and at last , specifications of MMC/SD is different from Memory Stick pro/pro duo ?
if yes where can i get Stick memory specs , seems it is faster than others ....
i need little help in these different speed grades ...