Teensy 4.0 with Nextion 10.1" Intelligent Series - Teensy HWSERIAL Rx Trouble

Jgolightly

New member
Hi all,

I am using a Teensy 4.0 with a Nextion 10.1" Intelligent Series touch screen. I originally created the project on an Arduino Uno and switched to the Teensy. Everything is working as expected (after some fixes) except for the Teensy receiving data from the Nextion display. I put my scope on the output of the Nextion and I am getting the expected signals when a press/release event happen. I have tried Serial1 and Serial2. Both work sending data to the Teensy, but nothing seems to work to receive data from the Nextion.

I feel as though I am missing something... obviously; my suspicion is that the problem is in this function.

nexLoop(nex_listen_list);

I have never told nexLoop which pin to listen on, I assume that is buried somewhere in a library that I have not been able to locate. The Rx pin by default is pin 0 on the Uno.

I am using https://github.com/itead/ITEADLIB_Arduino_Nextion library.

Has anyone else come across this issue? My Code is attached. 8_Thermocoup..... is the main, others are functions. Please ignore any other errors you might see.

Thanks
Jason

View attachment hmi_update.inoView attachment 8_Thermocouple_Tracker_Nextion_HMI_8_5_2020_teensy40.inoView attachment MaxAveMin.inoView attachment read_TCs.ino
 
Hi again everyone,

Even though I had spent all day yesterday searching, I could not find the answer. Of course, as soon as I post my question... I figure it out.

The problem is in nexConfig.h

The line that reads "#define nexSerial Serial" is the issue. I tried using Serial1 and it still did not work. When I switched it to Serial2, it started working.

Hope this helps someone somewhere sometime.

Thanks
Jason
 
My thinking is that it really should have worked on Serial1 all along as it defines the same pins as Serial does. Is my thinking correct?
 
careful, it looks like Nextions are 5v devices. Teensy 4 is NOT 5v tolerant, you may need level shifters? Maybe OK if you don't hook up Nextion Tx to T4.

edit: at least on some Nextions, the serial port logic is 3.3v
 
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The Nextion Intelligent Series is 5v i/0, the enhanced, which only goes up to 7", is 3.3v i/o. Both need 5v power to drive them. The 10" needs 5v at 2A. Rather a greedy device!
 
The Nextion Intelligent Series is 5v i/0, the enhanced, which only goes up to 7", is 3.3v i/o. Both need 5v power to drive them. The 10" needs 5v at 2A. Rather a greedy device!

10.1 " intelligent and capacitive one does not draw 2A but 0.773 Amps at 5V. I did measure it on a UNI-T lab power supply.
 
Nextion 10 inch Power Requirement.png
You are correct the typical current consumption is 800mA,
but a 5V2A power supply is recommended.
 
View attachment 26920
You are correct the typical current consumption is 800mA,
but a 5V2A power supply is recommended.

Well, this is a long time debate. I usually tend to use max 75 of 100% as safety zone, so a 1A power source will do just nice. I even powered this display from laptop USB via TTL usb to serial converter but it is risky indeed.
I just ordered my first Teensy ever , a 4.1 one for my hamradio hobby as developer. As RF point of view, the first thing to care of is the SMPS power supply as RF noise , ripple and impedance. The experience tells me that many of us do fail selecting a proper power supply, where sudden instability or strange behavior can happen.
Willing to develop a different kind of homebrew hamradio shortwave radio transceiver, I will surely be proactive on pjrc forum as I am a newbie on teensy, especially on audio Hilbert coefficients as IQ 90 degrees phasing!
Best regards, Gabriel yo8rxp
 
Welcome to Teensy, the forum is excellent for support. The T4.1 is a fantastic beast!!
I am using one, along with a Nextion 10" display. and T3.2/T3.1s as slave devices for a Home Heating Management system I am developing.
It may ultimately manage other things besides heating in the future.
 
Welcome to Teensy, the forum is excellent for support. The T4.1 is a fantastic beast!!
I am using one, along with a Nextion 10" display. and T3.2/T3.1s as slave devices for a Home Heating Management system I am developing.
It may ultimately manage other things besides heating in the future.
I aint see a way to reply except "reply with quote" , sorry about !
Did you set heating each room using floor heating system or using plain heat radiators with dallas temp sensors to cutoff each room when setup temp is True +- 0.2 C ?
I mean, all of us should go green while is not too late ( maybe is too late ). No reason to heat up a room if aint needed ! I see no reason for humans to heat up a room above 22 Celsius but I know a lot of my friends heating up to 25 C . Grrrrr !
Regards, Gabriel
P.S. Now I see simple reply button, but not prior.
 
It's will work with hot water circulating heat radiators. I already, when I put in the heating system, had many zones set up. I don't see the need to heat bedrooms in the day when they are not being used, nor to
heat living rooms in the middle of the night. So each room will have it's own heating needs.
Also we don't live in the bathroom so only heat it above a low ambient level when we are using it. It needs an ambient level since going to the loo, we would not me in there long enough for the room to heat up.
Also when taking a bath a higher temperature is probably required. So a separate environment for the bathroom is required.
 
I am a bit disappointed by audio shield design. :mad: It seems that stereo audio jack ground a is virtual ground , aka floating ground not connected to teensy GND. (1.7 V diff and also is paint marked on botom too) .Therefore I have fried my audio shield but lucky me there are some companies in my country selling it, so delivery time will be much shorter. Long story short, the 3.3 rail suddenly become shorted inside audio chip. To be honest, I do not see the logic behind having audio output virtual ground ! . Gotta buy some audio 600 ohms 1:1 small transformers to isolate it ! hope pjrc to change the design asap ! Regards, Gabriel
 
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