On Tue, Feb 23, 2021 at 5:59 PM ha ppay <andocn...@gmail.com> 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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAOCHtYgoybBP5q1yg4emeV0_%2BBN3S0i2_oN%3D7SAwC91SS4NLKA%40mail.gmail.com.
