MAPG
Posts: 4
Joined: Wed Nov 15, 2017 4:39 pm

CM3 eMMC problems

Wed Nov 15, 2017 5:18 pm

Hi, I'm running into trouble when it comes to using the internal eMMC on the CM3 v1.0.

I'm developing a prototype for a commercial product based on the CM3, and I'm using a custom carrier board to do so. I'm able to load the eMMC in my W10 computer as a mass storage device using the rpiboot utility. I've succeeded at flashing my own custom buildroot image and the latest raspbian image (both run on a standard RPi3), but I end up running into the following eMMC-related errors AT RANDOM (sometimes everything works fine, sometimes the errors come up) shortly after the CM3 boot:

mmc0: error -110 whilst initialising MMC card
mmc0: timeout waiting for hardware interrupt
-----lots of junk-----
[ 60.951329] mmc0:>cmd op 6 arg 0x3b30201 flags 0x49d - resp 00000000 00000000 00000000 00000000, err -110
[ 60.960891] mmc0: =========== REGISTER DUMP ===========
[ 60.966112] mmc0: SDCMD 0x00004806
[ 60.969595] mmc0: SDARG 0x03b30201
[ 60.973079] mmc0: SDTOUT 0x017d7840
[ 60.976562] mmc0: SDCDIV 0x00000003
[ 60.980046] mmc0: SDRSP0 0xffffffff
[ 60.983529] mmc0: SDRSP1 0x0000ff7f
[ 60.987013] mmc0: SDRSP2 0xc4800002
[ 60.990496] mmc0: SDRSP3 0xffffffff
[ 60.993980] mmc0: SDHSTS 0x00000040
[ 60.997463] mmc0: SDVDD 0x00000001
[ 61.000946] mmc0: SDEDM 0x00010801
[ 61.004429] mmc0: SDHCFG 0x0000040e
[ 61.007912] mmc0: SDHBCT 0x00000006
[ 61.011396] mmc0: SDHBLC 0x00000001
[ 61.014879] mmc0: ===========================================
[ 61.020700] sdhost_busy_irq: intmask 440, data (null)

The CM3 then hangs completely and spits this out every ~20 secs.

I've checked my power supply board and everything seems to be fine, so I'm now dumbfounded about what to do to solve this eMMC reliability issue. It would be great to get some help to get back on track.

Thank you.

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1210
Joined: Sat Sep 10, 2011 11:43 am

Re: CM3 eMMC problems

Wed Nov 15, 2017 8:12 pm

Do you get the same problem when the CM3 is moved to the CMIO3 board?
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

MAPG
Posts: 4
Joined: Wed Nov 15, 2017 4:39 pm

Re: CM3 eMMC problems

Thu Nov 16, 2017 8:17 am

I don't have the CMIO board, I made a custom carrier myself. I do have several CM3 with me and I get the same eMMC errors in each one of them.

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1210
Joined: Sat Sep 10, 2011 11:43 am

Re: CM3 eMMC problems

Thu Nov 16, 2017 8:43 am

I'm guessing it's likely to be a problem with the eMMC disable input or the power supply. I assume you've wired up the eMMC disable the same as on the CMIO board?

Gordon
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

MAPG
Posts: 4
Joined: Wed Nov 15, 2017 4:39 pm

Re: CM3 eMMC problems

Wed Nov 22, 2017 8:45 am

Sorry about taking so much time to reply, I was busy with other tasks.

There seems to be nothing wrong with the power supply. I wasn't exactly replicating the CMIO board USB BOOT ENABLE schematic section, but now I am. EMMC_EN and EMMC_DIS behaviour seems to be alright, but now I can only access the eMMC from my PC like 1 out of every 10 times I execute rpiboot. What can be causing this unreliable behaviour?

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1210
Joined: Sat Sep 10, 2011 11:43 am

Re: CM3 eMMC problems

Wed Nov 22, 2017 11:54 am

That's almost definitely caused by poor signal integrity for the USB signals. I had this problem with a cheap USB cable because of the differential impedance being double what the spec says...

Make sure you've got a good quality USB cable

Gordon
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

MAPG
Posts: 4
Joined: Wed Nov 15, 2017 4:39 pm

Re: CM3 eMMC problems

Mon Nov 27, 2017 9:04 am

We ended up getting a CMIO v3 board and everything works as expected. I think the USB routing in our PCB prototype didn't meet the standards so as you said the communication was wonky. Thank you for your time.

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