• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 99 subscribers
  • Views 2914 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

GPMC Beaglebone Black

Jack Zhang2
Intellectual 450 points

Hello,

Does anyone to know how to get GPMC to work on the Beaglebone black?

Because GPMC cannot be in use while eMMC is being used.

I looked around on the beaglebone forum, and they suggested to have the eMMC on reset, but I couldn't find any actually managed to get it working. Did anyone here manage to do so?

Thanks!

Jack

  • 0
    Intellectual 450 points

    Let me add some details.

    Currently using Angstrom as the OS (June 6, 2013 version).

    The device tree file that I am using works perfectly on a Beaglebone white, but not with Black (due to the MMC issue, of course).

  • 0 in reply to Jack Zhang2
    Intellectual 450 points

    Just an update.

    I managed to get eMMC disabled by adding the following line in my uENV file:

    optargs=quiet drm.debug=7 capemgr.disable_partno=BB-BONE-EMMC-2G
    This works, however, sometimes the BBB will crash. For example, if I have the input connected to the board with the circuit board and the BBB grounded together, when I start the BBB after about 5 minutes or so, it will stop running. Leaving only the USR3 AND USR2 LED on.
  • 0 in reply to Jack Zhang2
    TI__Guru**** 393215 points
    This is a copy from another thread which discussed this issue:
     
    It's not possible to use the GPMC directly on BB Black due to pinmuxing conflicts (there is an eMMC memory attached to MMC1, which overlaps with GPMC_AD[0:7]). Theoretically it should be possible to boot via an SD card on MMC0. For this purpose SYSBOOT[0:4] pullups/pulldowns should be changed according to the table on page 6 of the BB Black schematics, from 11100b to 11000b. eMMC can be held in reset by modifying MLO/u-Boot so that GPMC_A4 is pinmuxed to GPIO and driven high (eMMC_RSTn signal). The bad news is that GPMC_A4 is not available on the expansion headers. A check should also be made of the state of eMMC I/O signals when the chip is in reset. eMMC pullups may also need to be removed.