RPI 3B+ and RPI 7'' touchscreen

Diy and Tweaks
1

Hi together,

I just got the Raspberry 7’’ touchscreen running.
I’m almost certain that the following tip can also be found here in community, but so be it…

By installing the touchscreen plugin, I achieved my goal very quickly in my second attempt ;-).
After I downloaded the latest version of the Volumio image (3.611), I created a user userconfig.txt and “called” the following overlay:
dtoverlay=hdmi,off

Background:
The Readme contains the following 2 notes:

  1. grafik

  2. grafik
    grafik733×405 66.3 KB

I can’t say whether dtoverlay=hdmi,off is absolutely necessary.
All I can say is that’s how it works for me.

Because Hifiberry AMP100 uses i2c1, I’ll change the I2C-GPIOS used by Touchscreen to i2c0.
grafik

kind regards
Klaus

2

It looks like the rpi 7’’ touchscreen display works even without the i2c connections.
The question now is: why is that?

grafik
grafik701×542 34.2 KB

3

The dedictated cables for SDA and SCL are only required for old Model A/B boards where the DSI connector does not have I2C connections. With your Pi 3B+ SDA and SCL signals are already transmitted via the DSI ribbon cable. The cables for SDA and SCL should then not be used.

4

I think that’s a misunderstanding. The note is related to Volumio images that already provide an option to display Volumio’s UI on a locally connected display on Volumio’s system settings page. IIRC that option is in the section “Video Output Options” and called “User Interface Via HDMI” but is currently not available on Pi based Volumio systems (so you would not find it on your system :wink:) - hence the need for the Touch Display plugin on such systems.

tl:dr Using the overlay “hdmi” should not be required.