Monitor Baud rate 1000000 show giberish

[xinkiknix]

Describe the problem

When baud rate is set to 1000000 both in monitor as in application, the show information is not useable.
460800 works fine. I did not test the full range :-(

To reproduce

Set Baud rate to 1000000

Expected behavior

Showing standard ASCII set

Arduino IDE version

Original report

2.0.0 rc7

Last verified with

7c86f1f

Operating system

Windows

Operating system version

11

Additional context

PC windows 11 build 22000
i7-8700 @3.20Ghz
8GB RAM
SSD

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details

[per1234]

Thanks for your report @xinkiknix.

Please tell me which Arduino board you are using.

Please provide a sketch I can use to reproduce the problem.

---

Similar report: #427

[xinkiknix]

I am using ESP32 & ESP32-S3, I will see if I can create a minimal sketch showing this problem

[xinkiknix]

This will do:

void setup() {
  Serial.begin(1000000);
  Serial.println(__FILE__);
  int i = 0;
    for (int i = 48; i<126; i++){
    for (int j = 0; j < 80; j++){
      int pos = i+j;
      if (pos > 126){pos = pos%126;pos+=48;} 
    Serial.print(char(pos));
    }
    Serial.println();
  }
}
void loop() {}

at 1000000baud I get:

or (second run)

2000000 gives :

other baud rates work fine

[per1234]

Perfect, thanks! I am able to reproduce the issue with the "NodeMCU" ESP32 I have here.

I tried it with an assortment of other boards, including official boards as well as a few 3rd party boards and was not able to reproduce it with any of the others.

However, I was able to reproduce it by connecting a Silicon Labs CP2102 USB to serial adapter module to a Pro Mini board. My ESP32 board also uses the CP2102. The problem did not occur when I used an FTDI FT232R module or a WCH CH340 module with the Pro Mini. So this tells me that the problem is likely associated with the CP2102, not with the ESP32.

Does your ESP32 board have a CP2102 USB to serial chip on it @xinkiknix?
It is a 5 mm square chip (QFN28) near the USB connector on the board:

[xinkiknix]

Yes the ESP32 has a CP2102 module, the ESP32-S3 has CP2102N version. both show same behaviour