07-05-2017, 10:06 AM
(07-05-2017, 08:02 AM)joe Wrote: I read the RK3328 datasheet MicroSD iCompatible with SD 3.0 this mean maybe faster than pinea64 the pinea64 is used SD 2.0
"Compatible" is slightly differing than "uses". UHS-I is effectively the SD 3.0 specification for all intents and purposes. All 3.0 devices are "compatible" with the 2.0 interface, they just are able to run faster on a 3.0 bus.
As an aside to all- when you're talking <X>MBps on a given specification, that is the signalling rate of the interface. There are NO assurances that any given device, including the eMMC cards, will leverage all of that speed. You must take into account number of lanes (bits) for the data, how many I/O operations per second the device will provide, etc. If the eMMC does only 500 IOPS for the read, for example, an A1 SD card will VAPORIZE it on read (1500 IOPS minimum on read to make an A1 cert...) if you're operating in 4 bit mode against 4 or 8-bit mode on the eMMC. This is because it can address 3 times the requests, saturating the SD/MMC bus where the eMMC in this example can't even get there.
Empirical (measured) analysis of both interfaces is in order, to be honest.