I want to use gpio0_30 for something in an app I have written. I am unable to unexport the gpio, but can export/unexport others...
I am using a Beaglebone Black, running:
dogtag:[BeagleBoard.org Debian Image 2017-03-19]
bootloader:[/dev/mmcblk0]:[U-Boot 2017.03-00002-gd12b1519b4]
bootloader:[/dev/mmcblk1]:[U-Boot 2018.03-00002-gac9cce7c6a]
kernel:[4.4.54-ti-r93]
nodejs:[v4.9.1]
BB GPIO unable to unexport gpio
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- smbrandonjr
- Posts: 27
- Joined: Thu Oct 11, 2018 12:44 am
BB GPIO unable to unexport gpio
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- drewfustini
- Posts: 944
- Joined: Sat Dec 26, 2015 1:19 pm
Re: BB GPIO unable to unexport gpio
This version is u-boot bootloader on the eMMC is too old.
Please run this command on your BeagleBone to disable the old version of the u-boot bootloader on the eMMC:
sudo dd if=/dev/zero of=/dev/mmcblk1 bs=1M count=10
This will cause the newer u-boot bootloader on the SD card to be used.
Please run this command on your BeagleBone to disable the old version of the u-boot bootloader on the eMMC:
sudo dd if=/dev/zero of=/dev/mmcblk1 bs=1M count=10
This will cause the newer u-boot bootloader on the SD card to be used.
- smbrandonjr
- Posts: 27
- Joined: Thu Oct 11, 2018 12:44 am
Re: BB GPIO unable to unexport gpio
Hi,
Thank you for this step. I am just now able to get around performing it and it got me where I needed to be. Thank you.
I am new to beaglebone and am curious if I will be able to use gpio0_2, gpio0_3, gpio0_4, and gpio0_5 or will those always be reserved for eMMC?
Thank you for this step. I am just now able to get around performing it and it got me where I needed to be. Thank you.
I am new to beaglebone and am curious if I will be able to use gpio0_2, gpio0_3, gpio0_4, and gpio0_5 or will those always be reserved for eMMC?
- drewfustini
- Posts: 944
- Joined: Sat Dec 26, 2015 1:19 pm
Re: BB GPIO unable to unexport gpio
if you boot from MicroSD, then you can reuse the eMMC pins.
Here is how to to disable eMMC in the u-boot bootloader:
https://elinux.org/Beagleboard:BeagleBo ... rd_devices
Here is how to to disable eMMC in the u-boot bootloader:
https://elinux.org/Beagleboard:BeagleBo ... rd_devices
- smbrandonjr
- Posts: 27
- Joined: Thu Oct 11, 2018 12:44 am
Re: BB GPIO unable to unexport gpio
how can i release these pins so that i may control them?
- drewfustini
- Posts: 944
- Joined: Sat Dec 26, 2015 1:19 pm
Re: BB GPIO unable to unexport gpio
Please paste the content of /boot/uEnv.txt
I should be able to advise which lines that you should change
I should be able to advise which lines that you should change
- smbrandonjr
- Posts: 27
- Joined: Thu Oct 11, 2018 12:44 am
Re: BB GPIO unable to unexport gpio
I'd really like to free up as many of the GPIO as possible...I need to be able to use the ethernet adapter and write my OS to the eMMC...other than that, I would like to be able to use it as my own defined input or output if it will be allowed.
Which of these gpio remain available and how do I free them up?
Which of these gpio remain available and how do I free them up?
- drewfustini
- Posts: 944
- Joined: Sat Dec 26, 2015 1:19 pm
Re: BB GPIO unable to unexport gpio
I think you have disabled as many of the peripherals as you can, per your uEnv.txt screenshot.
Which pins are you trying to use?
Which pins are you trying to use?
- smbrandonjr
- Posts: 27
- Joined: Thu Oct 11, 2018 12:44 am
Re: BB GPIO unable to unexport gpio
Drew,
Thanks for getting back to me. Until I stumbled across your Twitter, I didn't realize your association to OSHPark. Ironically, the hobby project I'm working on involves a PCB I had OSHPark create for me (very happy with the results). Unfortunately I made some oversights regarding which GPIOs I would have available and need to create a new version of my PCB.
I need to be able to use at least 45 GPIO for my project. I am not married to any specific GPIO except Serial4_RX and Serial4_TX.
Onboard platforms I want to utilize on by BB Black are the eMMC, Ethernet, the Type A USB, and the Mini B USB (my lack of understanding of the BB platform and embedded hardware in general prevents me from understanding whether modifying/utilizing the accessible GPIO with my application would impact any of those onboard devices...well I realize the eMMC platform based on our previous discussions but am unsure on the others)
Thanks for getting back to me. Until I stumbled across your Twitter, I didn't realize your association to OSHPark. Ironically, the hobby project I'm working on involves a PCB I had OSHPark create for me (very happy with the results). Unfortunately I made some oversights regarding which GPIOs I would have available and need to create a new version of my PCB.
I need to be able to use at least 45 GPIO for my project. I am not married to any specific GPIO except Serial4_RX and Serial4_TX.
Onboard platforms I want to utilize on by BB Black are the eMMC, Ethernet, the Type A USB, and the Mini B USB (my lack of understanding of the BB platform and embedded hardware in general prevents me from understanding whether modifying/utilizing the accessible GPIO with my application would impact any of those onboard devices...well I realize the eMMC platform based on our previous discussions but am unsure on the others)
- drewfustini
- Posts: 944
- Joined: Sat Dec 26, 2015 1:19 pm
Re: BB GPIO unable to unexport gpio
Hello - I am not certain if it is possible to have 45 GPIOs and eMMC.smbrandonjr wrote:Drew,
I need to be able to use at least 45 GPIO for my project. I am not married to any specific GPIO except Serial4_RX and Serial4_TX.
Onboard platforms I want to utilize on by BB Black are the eMMC, Ethernet, the Type A USB, and the Mini B USB (my lack of understanding of the BB platform and embedded hardware in general prevents me from understanding whether modifying/utilizing the accessible GPIO with my application would impact any of those onboard devices...well I realize the eMMC platform based on our previous discussions but am unsure on the others)
I would be a question of the cross section between:
eMMC and HDMI
and
Digital I/O
I would recommend posting on the BeagleBoard.org community mailing list as it has a much wider audience including Jason Kridner (co-creator of the BeagleBone) and Robert Nelson (who creates the Debian images and kernel builds):
http://bbb.io/discuss
Please be positive and constructive with your questions and comments.