Boot Issue from EMMC on i.MX6Q

[diegobovi85]

Good morning,

we are investigating a problem related to the start-up of a IMX6Q processor booting from the eMMC device. We have about 20 boards among a lot of 300 pieces that show the same behaviour.

The iMX6Q processor is installed on a custom CPU board. The eMMC device is the SANDISK p.n. SDIN8DE2-4G.

After the power-up the BOOTSEL are correctly sampled and the iMX start the operation in order to identify the eMMC device installed and connected to the SD4 interface.

Following the flowchart of the iMX  internal BOOT-ROM, the processor sends the CMD0 (GO_IDLE_STATE) command, then follows a loop of the CMD1 command (SEND_OP_COND).

This command is sent until the eMMC sets to logic level 1 the MSB of the OCR register. Then the processor sends the CMD2 command in order to identify the eMMC device.

At the end of this command the clk signal driven by the iMX6Q stops and then the processor goes in serial download state waiting for USB connection.

This Issue is very critical for us and we look forward to receive a feedback as soon as possible.

[igorpadykov]

Hi Diego

issue may be related to poor soldering so one can try to resolder

chips. Also one can consider similar issue on

https://community.nxp.com/thread/332110 

Best regards
igor
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[diegobovi85]

Hello Igor, 

is there any guidelines or constraints to connect the emmc device to the imx6q cpu? I mean, for example, external pull-ups, pull-downs, termination resistors, and so on.

kind regards

Diego

[igorpadykov]

Hi Diego

for example of connection one can look at  iMX6Q-SABRE-SDB-DESIGNFILES

Design files, including hardware schematics, Gerbers, and OrCAD files for i.MX 6Quad (i.MX 6Dual emu...

emmc layout rules in sect.3.6.8 High speed signal routing recommendations

IMX6DQ6SDLHDG, Hardware Development Guide for i.MX 6Quad, 6Dual, 6DualLite, 6Solo Families of Applic...

Best regards
igor

[diegobovi85]

Hello Igor,

we asked to our contract manufacturer to analyze the PC boards with the emmc issue. They performed an X-ray analysis to check the components soldering quality of the imx6q cpu and emmc device. All the 5 analyzed boards did not have soldering issues. We also tried to change the emmc component, so we removed the SANDISK SDIN8DE2-4G and we installed the MICRON MTFC4GACAJCN device, but the behavior did not change.

Our problem is not linux related, since it appears at the very beginning during the execution of the imx boot rom code.