noend wrote: Dmitri wrote:
In my theory, the SPI can work @ 40 MHz quite good.
I'll then configure it to work @ 40MHz.
so I suppose the Sandisk MicroSDHC is running at that speed?
Actually, they all may not, but they work indeed. I read that 25 MHz is the limit. It is not
The clock signal looks horrible at a 60MHz oscilloscope.
I use SPI clock speed switching. I found it usefull to run it at lower speeds for FAT operations but at highest speed for miltiblock writes.
BTW, I never test if the block was accepted by reading a reply byte. I could, but I do not. It works quite reliable with many different transflash cards bought on Internet.
The only FAT operation that I need is finding the start sector of a file that I put onto the card before. I start with this sector. Thus, the card is still readable unter Windoze.