Teensyduino 1.57 Released

I installed Beta 3 and everything worked. But I got tired of being nagged about updating my boards, so I reverted to 1.5.7 (awaiting release).
I got this error:
exec: "C:\\Users\\BobbaFett\\AppData\\Local\\Arduino15\\packages\\teensy\\tools\\teensy-tools\\1.57.2/precompile_helper": file does not exist

Compilation error: exec: "C:\\Users\\BobbaFett\\AppData\\Local\\Arduino15\\packages\\teensy\\tools\\teensy-tools\\1.57.2/precompile_helper": file does not exist

So back to Beta 3 to get some work done.

- Wes, W5ZZO
exec: "C:\\Users\\BobbaFett\\AppData\\Local\\Arduino15\\packages\\teensy\\tools\\teensy-tools\\1.57.2/precompile_helper": file does not exist

Perhaps Windows Defender or other anti-virus software got a little overly ambitious and deleted or "quarantined" it?
I'll holler uncle.
I redid the process (0.58.3 -> 1.57.2) and got no error.
I have no idea what happened, but I am back on 1.57.2 and this time it works.

- Wes, W5ZZO
Windows 10, Arduino IDE 2.2.1, Teensy 1.57.2.

Back to 1.57.2 since the more recent versions are not working. So I tried EchoBoth.ino again.

I made some changes :

HWSERIAL is Serial1, and I set LED to ON when receiving through Serial and OFF when receiving through HWSERIAL.

[Correction] if I replace Serial1 by SerialUSB1 and I quit Arduino IDE to use external serial terminals (COM8 and COM9), it works fine.

Dual Serial mode -> get COM8 for Serial and COM9 theorically for Serial1.

Serial Monitor used. It connects to teensy port "COM8 Dual Serial (Teensy 4.1)". It happens to trigger USB reception and LED is set ON.

Cannot connect to serial port "COM8" because of teensy port I guess.

Can connect to serial port "COM9" but get no reception on teensy and LED is never set OFF.

Source :
const int ledPin = 13;
// set this to the hardware serial port you wish to use
#define HWSERIAL Serial1
void setup() {
  // initialize the digital pin as an output.
  pinMode(ledPin, OUTPUT);
void loop() {
  int incomingByte;

  if (Serial.available() > 0) {
    digitalWrite(ledPin, HIGH);   // set the LED on
    incomingByte = Serial.read();
    Serial.print("USB received: ");
    Serial.println(incomingByte, DEC);
    HWSERIAL.print("USB received:");
    HWSERIAL.println(incomingByte, DEC);
  if (HWSERIAL.available() > 0) {
    digitalWrite(ledPin, LOW);   // set the LED off
    incomingByte = HWSERIAL.read();
    Serial.print("UART received: ");
    Serial.println(incomingByte, DEC);
    HWSERIAL.print("UART received:");
    HWSERIAL.println(incomingByte, DEC);

Edit: trying Triple Serial mode. Worst case, no reception at all on any teensy or serial ports. *sigh*


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I'm not sure why it's not working with 1.58.

But to quickly clear up one minor thing...

COM9 theorically for Serial1.

Serial1 is always the hardware serial RX1 and TX1 pins.

In USB Dual Serial, the 2nd serial port is SerialUSB1.

In USB Triple Serial, the 2 extra ports are SerialUSB1 and SerialUSB2.
Yes, I noticed I had to replace Serial1 by SerialUSB1 to have COM9 working but thanks for the clarification as I didn't know it.
Looking at this again. Pretty clear the COM9 problem was use of Serial1 rather than SerialUSB1. That leaves the COM8 matter. Unclear to me if "Cannot connect to serial port "COM8" because of teensy port I guess" means Arduino IDE Serial Monitor can't connect, or if "external serial terminals" are the thing that can't connect.

Arduino IDE automatically reconnects the Serial Monitor after upload, if that tab is still open (which it usually is in the course of ordinary usage). In that case an external program would indeed be unable to connect, because Arduino IDE quickly reconnects the moment Teensy reboots and starts running the freshly uploaded program. Typically reconnect happens in less than 2 seconds, paced mostly by the speed of Windows detecting the USB device and loading drivers. But if the Serial Monitor tab is closed, then Arduino IDE should not tie up COM8 and a non-Arduino program should be able to use COM8.

But not all external programs (no idea what software is really used here) handle a COM port disappearing while they're using it. Windows 7 and 8 also handle that situation *very* badly, but this is said to be running on Windows 10.

Without further detail, I'm going to take this off my list of issues to investigate.
Having COM9 connexion but receiving nothing was clearly due to using Serial1 instead of SerialUSB1, which is my mistake and is now fully resolved in that regard.

As for COM8, the issue is that Arduino IDE's Serial Monitor was automatically connecting to Teensy Dual Port COM8/COM9. Now under 0.59.5, if I close that Serial Monitor, I can now use COM8 from another terminal (Tera Term) so everything is okay now.

I'm not considering getting back to 1.57/58.x.