SD/MMC and uSD cards
- COM Carrier Board V1
- COM Carrier Board V2
- uCOM Carrier Board V3
The COM Carrier Board V1 has two slots for external memory cards – a slot for the uSD card on the top of the carrier board and a slot for the full size SD/ MMC cards on the bottom side. Note that only one of the slots can be used at a time.
| Board | U-Boot ≤ 2017.03 | U-Boot = 2018-03 | Linux ≤ 4.14.98 |
|---|---|---|---|
| iMX6 SoloX COM | mmc dev 0 | mmc dev 1 | /dev/mmcblk1 |
| iMX6 Quad COM | mmc dev 0 | mmc dev 0 | /dev/mmcblk1 |
| iMX6 DualLite COM | mmc dev 0 | mmc dev 0 | /dev/mmcblk1 |
| iMX6 UltraLite COM | mmc dev 0 | mmc dev 1 | /dev/mmcblk0 |
| iMX7 Dual (u)COM | mmc dev 0 | mmc dev 0 | /dev/mmcblk0 |
A uSD or a full size memory card (SD/MMC) is required.
The COM Carrier Board V2 has one uSD slot for external memory cards on the top of the carrier board. Note that the uSD card slot is no longer available for the iMX6 UltraLite COM board as it is used for the M.2 connector instead.
| Board | U-Boot = 2018-03 | U-Boot ≥ 2020.04 | Linux ≥ 4.9.11 |
|---|---|---|---|
| iMX6 SoloX COM | mmc dev 1 | mmc dev 3 | /dev/mmcblk3 |
| iMX6 Quad COM | mmc dev 0 | mmc dev 2 | /dev/mmcblk2 |
| iMX6 DualLite COM | mmc dev 0 | mmc dev 2 | /dev/mmcblk2 |
| iMX6 UltraLite COM | mmc dev 1 | N/A | N/A |
| iMX7 Dual (u)COM | mmc dev 0 | mmc dev 1 | /dev/mmcblk1 |
| iMX7ULP uCOM | N/A | N/A | N/A |
| iMX8M Quad COM | N/A | N/A | N/A |
| iMX8M Mini uCOM | mmc dev 0 | mmc dev 1 | /dev/mmcblk1 |
| iMX8M Nano uCOM | mmc dev 0 | mmc dev 1 | /dev/mmcblk1 |
The iMX8M Quad COM board does not support uSD card as the pins are used for the M.2 connector instead.
A uSD memory card is required.
The uCOM Carrier Board V3 has one uSD slot for external memory cards on the top of the carrier board. As the name suggests, the uCOM Carrier Board only works with boards in the uCOM form factor.
| Board | U-Boot = 2021-04 | U-Boot ≥ 2022.04 | Linux ≥ 5.4.24 | Linux ≥ 6.1 |
|---|---|---|---|---|
| iMX8M Mini uCOM | mmc dev 1 | mmc dev 1 | /dev/mmcblk1 | /dev/mmcblk1 |
| iMX8M Nano uCOM | mmc dev 1 | mmc dev 1 | /dev/mmcblk1 | /dev/mmcblk1 |
| iMX93 uCOM | N/A | mmc dev 1 | N/A | /dev/mmcblk1 |
A uSD memory card is required.
U-Boot
The U-Boot has support for reading/writing memory cards.
Select device and show information
mmc rescan
mmc dev 0
mmc info
Device: FSL_SDHC
Manufacturer ID: 9
OEM: 4150
Name: AF UD
Tran Speed: 50000000
Rd Block Len: 512
SD version 2.0
High Capacity: No
Capacity: 981.5 MiB
Bus Width: 4-bit
List content
fatls mmc 0
1491 btngraph.gif
1396 btnlast.jpg
1266 btnminus.gif
1049 btnnext.jpg
1375 btnplus.gif
Linux
A new memory card will be detected automatically when it is inserted and a message like this one will be printed in the console (example is for iMX6 UltraLite COM board so mmc number is 0).
mmc0: host does not support reading read-only switch. assuming write-enable.
mmc0: new high speed SD card at address b368
mmcblk0: mmc1:b368 AF UD 981 MiB
mmcblk0: p1
To use the memory card it must first be mounted.
mkdir /mnt/sdcard
mount /dev/mmcblk0p1 /mnt/sdcard
The card is now mounted.
df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 3.4G 65.2M 3.2G 2% /
devtmpfs 340.0M 0 340.0M 0% /dev
tmpfs 500.1M 216.0K 499.9M 0% /run
tmpfs 500.1M 76.0K 500.1M 0% /var/volatile
/dev/mmcblk1p1 981.1M 3.8M 977.4M 0% /mnt/sdcard
List the content.
ls /mnt/sdcard
DEFCXX.JS TXTPSET.XML digi4.gif metaserv.js
DEFIO01.JS TXTPSIOA.XML error.gif metaset.htm
DEFIO02.JS TXTPSIOD.XML excanvas.js metaset.js
DEFIO03.JS TXTPSIOS.XML g_hor1.jpg metasys.htm
A good way to stress test the card is to copy a large file to the sdcard and compute a checksum of it (this should be done on a PC with a known good sdcard reader). It is then possible to calculate that checksum again on the target and make sure it matches.
md5sum /mnt/blob.bin
790bfdcdfac22a08ff27450d60be8a8f /mnt/blob.bin
As with the USB memory stick, don't forget to unmount it before physically removing it from the carrier board.
umount /mnt/sdcard