SCSI to IDE

[Chuck Guzis]

On 4 Dec 2010 at 18:50, Alexandre Souza - Listas wrote:

> Speed Class Rating
> The Speed Class Rating is the official unit of speed measurement for
> SD Cards, defined by the SD Association. The Class number represents a
> multiple of 8 Mb/s (1 MB/s), and meets the least sustained write
> speeds for a card in a fragmented state.

Using SPI, 400KB/sec is about the top rate for read, 200KB/sec for 
write.  If you can get 1MB/sec write speed, more power to you.  Most 
uC implementations get substantially less.

Most first-timers trying to wring performance using SPI out of an 
SDHC are surprised by the low transfer rate.

Cache-ing would help a lot.

--Chuck