Serial port on Teensy4.1

[pd0lew]

Hi all,

In my previous project with a Teensy 3.6 I used Serial port 4 at 2400 baud (Serial.begin(2400); Now I rewrite my program for a Teensy 4.1 and used Serial port 7, Serial7.begin(2400); This is not working ... what can be the problem?

Please help this is the only thing in my project what is not working.

Thanks,
Johan Holstein

 

[PaulStoffregen]

This is not working ... what can be the problem?

Maybe the wires aren't connected properly? Or maybe there's a mistake somewhere in your program? All it would take is one "Serial4" not changed to "Serial7", sort of like how your message has "Serial.begin(2400)" where you meant "Serial4.begin(2400)".

One thing I can confirm is not the problem is whether Serial7 works at 2400 baud. I tested it just now, using File > Examples > Teensy > Serial > EchoBoth, with these lines edited:

// set this to the hardware serial port you wish to use
#define HWSERIAL Serial7

void setup() {
	Serial.begin(9600);
	HWSERIAL.begin(2400);
}

It definitely works. I ran "seyon" on Linux to talk to the FTDI cable, and the Arduino Serial Monitor to talk to Teensy 4.1. Anything sent from either side appears on both.

 

[KurtE]

What is not working?
I did a quick and dirty program that opened Serial7 (pins 28 and 29)
First I verified that it should be able to create that baud.
Then I did simple output with counter and saw the data on Logic Analyzer.
Than added simple loop read and it is echoing...

So I think it is working

 

[pd0lew]

Hi all,

There where two issues at my place first the level shifter was wrong and second I reversed TX and RX. Everything is working fine now.

I feel a bit dumm and sorry for bothering the group!

Thanks for helping!

Best regards,
Johan

 

[KurtE]

Glad you have it working