topic Re: imx8mm POWER UP in i.MX Processors

imx8mm POWER UP

yheng_dd — Mon, 16 Jun 2025 08:48:19 GMT

hello

I am using MIMX8MM6DVTLZAA ，it can be download the system to EMMC ，also can download DDR and run it normally after powering on. But when powered on and started from EMMC, the serial port did not print and could not be started. When IMX8MM is powered on, SD3_CMD has a waveform。
boot_CFG is set to 0010101000100011, boot mode is 10; TESTMDOE pull down, JTAGnTRST pull up. May I ask where else there may be issues

Re: imx8mm POWER UP

JorgeCas — Mon, 16 Jun 2025 20:45:28 GMT

Hello,

When you say "also can download DDR and run it normally after powering on", do you mean that the bord is able to pass the DDR stress with DDR tool?

If the board is able to be flashed, the issue could be caused by UART connection to debug Cortex-A core.

Please check that you are using the same UART port used by default, if not a change should be done in image to use another UART port.

Also, please check that you do not have issues in UART-USB bridge.

Best regards.

Re: imx8mm POWER UP

yheng_dd — Tue, 17 Jun 2025 06:06:23 GMT

After downloading uboot to DDR, I put the kernel and DTP into DDR through the network, and then mounted the file system on the network to run. The entire IMX8MM motherboard can run normally, and the DDR throughput is also normal during testing. At this point, when I checked the files in EMMC, they were all normal and intact.
This IMX8mm motherboard schematic also references NXP's demo and the IMX8mm core board I previously used. The UART and IO usage is completely consistent with the development board, with the only difference being that the EMMC core board used is SDINBDA6-16G, while the EMMC I used is SDINBDG4-16G. The download uses uboot, and the kernel and file system are the same.
In the experiment, I set the bootmode to 01 download mode, and there was no signal from EMMC_CMD when powered on. I set it to 10 startup mode, and EMMC_CMD had a waveform when powered on. The core board is not connected to other boards. I directly soldered 5V power to the core board without UART and IO interference, and it cannot start.

Re: imx8mm POWER UP

JorgeCas — Tue, 17 Jun 2025 16:35:44 GMT

Hello,

Please confirm that the board does not go to serial download mode when the eMMC boot is selected.

When the board is not able to use a bootable image in boot source, it will go to SDP. This could help to confirm if the board is not able to communicate with memory.

Best regards.

Re: imx8mm POWER UP

yheng_dd — Fri, 20 Jun 2025 02:01:33 GMT

hello

when the eMMC boot is selected，At the moment of power on, EMMC_CM has a waveform signal of 100ms, and then IMX8MM is in download mode. Debug UART has no output and cannot input. If set to download mode, at the moment of power on, there is no signal from emmc_CM. Can you confirm if this is set to EMMC boot.
What tools should I use to try entering SDP

Re: imx8mm POWER UP

JorgeCas — Fri, 20 Jun 2025 16:03:07 GMT

Hello,

If there is communication to eMMC and then goes to SDP, means that there is not a bootable image in boot source, that is the boot flow. Please check that you are flashing the board correctly.

You are using the correct settings to select eMMC as boot source.

The way to enter in SDP is boot pins or do not find a bootable image in boot source.

Best regards.

Re: imx8mm POWER UP

yheng_dd — Tue, 24 Jun 2025 02:17:50 GMT

hello

The downloaded image file is working normally on the development board. The only difference between the board that cannot be started and the development board is that the EMMC model used on the development board is SDINBD6-16G, and the EMMC model used on the board that cannot be started is SDINBDG4-16G. Will there be any difference in the use of EMMC between these two models

Re: imx8mm POWER UP

yheng_dd — Tue, 24 Jun 2025 03:23:56 GMT

Can you please help to check my log below? Is there any configration change in uboot for emmc boot?

U-Boot SPL 2018.03-00001-gac924e6-dirty (Jul 26 2022 - 15:51:28 +0800)
power_bd71837_init
DDRINFO: start DRAM init
DRAM PHY training for 3000MTS
check ddr_pmu_train_imem code
check ddr_pmu_train_imem code pass
check ddr_pmu_train_dmem code
check ddr_pmu_train_dmem code pass
Training PASS
DRAM PHY training for 400MTS
check ddr_pmu_train_imem code
check ddr_pmu_train_imem code pass
check ddr_pmu_train_dmem code
check ddr_pmu_train_dmem code pass
Training PASS
DRAM PHY training for 100MTS
check ddr_pmu_train_imem code
check ddr_pmu_train_imem code pass
check ddr_pmu_train_dmem code
check ddr_pmu_train_dmem code pass
Training PASS
DRAM PHY training for 3000MTS
check ddr_pmu_train_imem code
check ddr_pmu_train_imem code pass
check ddr_pmu_train_dmem code
check ddr_pmu_train_dmem code pass
Training PASS
DDRINFO:ddrphy calibration done
DDRINFO: ddrmix config done
Normal Boot
Trying to boot from USB SDP
SDP: initialize...
SDP: handle requests...
Downloading file of size 884608 to 0x40400000... done
Jumping to header at 0x40400000
Header Tag is not an IMX image
Found header at 0x404289a0

U-Boot 2018.03-00001-gac924e6-dirty (Jul 26 2022 - 15:51:28 +0800)

CPU: Freescale i.MX8MMQ rev1.0 1800 MHz (running at 1200 MHz)
CPU: Commercial temperature grade (0C to 95C) at 40C
Reset cause: POR
Model: FSL i.MX8MM EVK board
DRAM: 2 GiB
MMC: FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... Card did not respond to voltage select!
*** Warning - No block device, using default environment

Failed (-5)
In: serial
Out: serial
Err: serial

BuildInfo:
- ATF 09c5cc9
- U-Boot 2018.03-00001-gac924e6-dirty

Detect USB boot. Will enter fastboot mode!
Net: No ethernet found.
Card did not respond to voltage select!
Block device mmc 0 not supported
bcb_rw_block, get_block_size return 0
read_bootctl, bcb_rw_block read failed
read command failed
Fastboot: Normal
Boot from USB for uuu
Hit any key to stop autoboot: 0
baudrate=115200
bootcmd=fastboot 0
bootdelay=2
ethprime=FEC
fdt_high=0xffffffffffffffff
fdtcontroladdr=b9f0a548
initrd_high=0xffffffffffffffff
loadaddr=0x40480000
soc_type=imx8mm
splashpos=m,m
stderr=serial
stdin=serial
stdout=serial

Environment size: 261/4092 bytes
Detect USB boot. Will enter fastboot mode!
Detect USB boot. Will enter fastboot mode!
flash target iu-boot=>
u-boot=>
u-boot=>
u-boot=>
u-boot=>

Re: imx8mm POWER UP

JorgeCas — Tue, 24 Jun 2025 19:17:14 GMT

Hello,

As you can see eMMC is not responding at initialization, this could be caused by a hardware issue or device tree configuration.

Please check that the board has the correct power configuration is correct to change from 3.3V to 1.8V.

Best regards.

Re: imx8mm POWER UP

yheng_dd — Wed, 25 Jun 2025 02:30:12 GMT

Thank you. The issue has been resolved
The difference in EMMC results in inconsistent uboot, causing IMX8MM to not find the file header during startup