Hi RobertCNelson Thank you for your confirmation. I checked my bbb, My eMMC was 8-bit Mode clearly. sudo cat /sys/kernel/debug/mmc0/ios clock: 50000000 Hz vdd: 21 (3.3 ~ 3.4 V) bus mode: 2 (push-pull) chip select: 0 (don't care) power mode: 2 (on) bus width: 2 (4 bits) timing spec: 2 (sd high-speed) signal voltage: 0 (3.30 V) driver type: 0 (driver type B) sudo cat /sys/kernel/debug/mmc1/ios clock: 52000000 Hz vdd: 21 (3.3 ~ 3.4 V) bus mode: 2 (push-pull) chip select: 0 (don't care) power mode: 2 (on) bus width: 3 (8 bits) timing spec: 1 (mmc high-speed) signal voltage: 0 (3.30 V) driver type: 0 (driver type B) regards,
2021年2月24日水曜日 11:30:50 UTC+9 ha ppay: > Hi Dennis Bieber > > Thank you for the detailed explanation of the SD card standard (class) and > features. > > > >The SanDisk Class 4 was easily 8 times faster than the Kingston Class > >10 for regular write, rewrite, and random write, and was also faster (if > >not as much) for read/reread/random read. > We will use it as a reference when selecting an SD card. > It turns out that like SD cards, MMCs have completely different transfer > rates. > >https://en.wikipedia.org/wiki/MultiMediaCard#Table > so many version... > Is the transfer speed of MMC completely different like SD card? > > regards, > 2021年2月24日水曜日 9:07:48 UTC+9 RobertCNelson: > >> On Tue, Feb 23, 2021 at 5:59 PM ha ppay <[email protected]> wrote: >> > >> > Hi RobertCNelson, >> > >> > I recently knew that the SD card was just one type of MMC, but I just >> made a mistake. Thank you for your advice. >> > yes, I knew that the am335x MMCHS supports up to 4-bit mode on SD >> cards. >> >> PS you can cat the debugfs to find out what mode this is in: >> >> MicroSD: 4-bit mode >> debian@bbb-pwr01-ser09:~$ sudo cat /sys/kernel/debug/mmc0/ios >> clock: 50000000 Hz >> vdd: 21 (3.3 ~ 3.4 V) >> bus mode: 2 (push-pull) >> chip select: 0 (don't care) >> power mode: 2 (on) >> bus width: 2 (4 bits) >> timing spec: 2 (sd high-speed) >> signal voltage: 0 (3.30 V) >> driver type: 0 (driver type B) >> >> eMMC: 8-bit mode >> debian@bbb-pwr01-ser09:~$ sudo cat /sys/kernel/debug/mmc1/ios >> clock: 52000000 Hz >> vdd: 21 (3.3 ~ 3.4 V) >> bus mode: 2 (push-pull) >> chip select: 0 (don't care) >> power mode: 2 (on) >> bus width: 3 (8 bits) >> timing spec: 1 (mmc high-speed) >> signal voltage: 0 (3.30 V) >> driver type: 0 (driver type B) >> >> If you can't read that, then update your fstab: >> >> debian@bbb-pwr01-ser09:~$ cat /etc/fstab | grep debug >> debugfs /sys/kernel/debug debugfs mode=755,uid=root,gid=gpio,defaults 0 0 >> >> Regards, >> >> -- >> Robert Nelson >> https://rcn-ee.com/ >> > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/c1718a11-0ba1-41ab-8eff-8ad6898195d3n%40googlegroups.com.
