Serial Strange Behavior

Please tell us which board you are using.
For CircuitPython issues, ask in the Adafruit CircuitPython forum.

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
adamj537
 
Posts: 6
Joined: Wed Jun 29, 2016 7:32 pm

Serial Strange Behavior

Post by adamj537 »

I have an Adafruit Feather M4 Express, and am using it with the Arduino IDE (instead of Circuit Python). I have installed Arduino IDE 1.8.16 with board package "Adafruit SAMD Boards (by Adafruit)." Other settings; Cache = enabled; CPU Speed = 120 MHz; Optimize = Small; Max QSPI = 50 MHz; USB Stack = Arduino.

In my final application, the Feather communicates with a .NET 5.0 desktop app using a serial port. However, when my app sends a message, the Feather sends nothing back. Additionally...

- Sending the same message with my .NET app to an Arduino UNO (with same firmware as the Feather) causes the UNO to respond as intended.
- Sending the same message with Bray's Terminal to the Feather does not work unless the DTR signal is asserted.
- Sending the same message with Bray's Terminal to an UNO causes the UNO to respond as intended (regardless of DTR).
- Sending the same message with Tera Term causes the Feather to respond as intended.
- An Adafruit Feather M0 Express has the same behavior as the Feather M4.

Can anyone give me more information about this behavior? Do I need to assert DTR in my .NET program? Can I disable DTR in the Feather?

Code to reproduce:

Code: Select all

void setup() {
	Serial.begin(115200);
}

void loop() {
	if (Serial.available()) {
		Serial.write(Serial.read());
	}
}

User avatar
adamj537
 
Posts: 6
Joined: Wed Jun 29, 2016 7:32 pm

Re: Serial Strange Behavior

Post by adamj537 »

Tested further today: Setting DTR in my .NET app causes the Feather to respond as intended (and prevents the UNO from receiving messages).

I can make this work, but it's weird. Is there a way to disable DTR in the Feather?

Locked
Please be positive and constructive with your questions and comments.

Return to “Feather - Adafruit's lightweight platform”