question

Simon Bendall avatar image
Simon Bendall asked

Venus on Pi with 3.5" GPIO screen

Hi all.

I've got Venus 2.42 running on a Pi3 B+, with a 3.5" GPIO LCD. After much faffing, I've got it displaying the output as per this image:

Unfortunately, that's as far as it gets. I've renamed the headless file, and that makes the last underscore stop flashing at boot, as if it crashes. With the headless file still there, it flashes and is responsive.

Everything else about it works fine - just no display. The remote console is working as it should.


Does anybody have any ideas?

Simon

Venus OSRaspberry Pi
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I'm still trying to figure out how you delete this headless file...

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Hi Simon!

For me also was complicated to work touchscreen 3.5 gpio. Here I published my solution: https://www.buentutorial.com/touchscreen-3-5-venus-en-raspberry/

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3 Answers
code-chief avatar image
code-chief answered ·

@Luis del Campo has already written the answer nicely in his linked blog post, but it's in not in English so I've summarized it here for convenience.

Instructions:

1. Insert the SD card into a PC and goto the Boot partition.

2. Download LCD-Show package, extract then copy the "tft35a-overlay.dtb" file from the "/usr" folder of the archive to the "/u-boot/overlay/" directory.

3. Edit the "/u-boot/config.txt" and update the "[all]" section as follows:

[all]
dtparam=spi=on
dtoverlay=tft35a, rotate-270
display_default_lcd=1

4. Put the SD card back in the Raspberry Pi, connect power and wait for it to boot.

5. Enable super-user mode by holding the right button/arrow on the Settings->General screen option "Access level" which defaults to "User+Installer", but will change to "Superuser" after a few seconds. New menu options will also appear.

6. Use the "Set root password" option to set a complex password for root (and login via SSH).

7. Enable the "SSH on LAN" option.

8. Login via SSH from the PC:

ssh root@venus.local

9. Install the touchscreen calibration tools:

opkg update
opkg install tslib-calibrate

10. Calibrate the screen:

ts_calibrate Tap

11. Disable headless mode and reboot to see:

mv /etc/venus/headless /etc/venus/headless.off
reboot


Note: Only changes to the original instructions are the removal of the export commands after installing the calibration tool. If it doesn't run then enter these commands and try again (you can run "export" to confirm they were set the same by default).

export TSLIB_FBDEVICE=/dev/fb0
export TSLIB_TSDEVICE=/dev/input/touchscreen0


Note: To re-calibrate the screen or run any other command-line utilities interactively on the touchscreen, re-enable headless mode:

mv /etc/venus/headless.off /etc/venus/headless
reboot


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Followed your steps using my RPI4 but couldn't get past step 9 as am getting failed to download. I can view the display but the touch is not working. Any help on how to opkg installed calibrate.


Thanks

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There was an issue with the last firmware and updating opkg. Once you upgrade the firmware - you should be able to run opkg again.
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The instructions above differ to those on the WiKi here. Anyone tell me which is the correct path to take?
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Can you please confirm that with the following, I should be seeing boot text when the Pi is starting as my display is blank? I think I have a Chinese clone of the MPI3501 Display that has a 2-pin fan connector and differs from the stock one ever so slightly. I can't for the life of me get it working with Victron but it works fine with a standard Pi Debian image.

/etc/venus/headless

win-20210929-19-57-20-pro.jpg

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Yes, when running headless you will see boot text and then a command prompt.

when running headles.off you will see boot text then the gui screen.

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lunatech avatar image
lunatech answered ·

i have the same problem with 3.5 inch screen. the touchscreen is working but the display won't. I tried connecting the pi on a hdmi and it worked fine. can anyone help? Thanks


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Based on my experience, I would give up now. It either works or it doesn't which could be down to the quirks in the LCD variant you have. I got one in from AliExpress and while it works fine with any Pi Debian image built with LCD support, I can't get it working with Victron at all and I've probably spent in excess of 10hrs trying.
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bigbadbob76 avatar image
bigbadbob76 answered ·

A blank screen suggests to me that the tft35a overlay is not suitable for your particular display.

Chinese clones rarely come with any useful technical info so you are left in the dark about how to drive them.

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