Serial Monitor not working with ESP8266

PlatformIO IDE
1

I’m having trouble using the Serial Monitor in PlatformIO. I used it last year for a project with no problems but am just getting back into things on a new project. I’m using a NodeMcu ESP8266 and am able to upload a basic blinking project just fine. However when I try to use the serial monitor (same port, baud rate matches the code) I don’t see any messages and it looks like the blinking code stops. If I open a different serial monitor like in Arduino thing seem to work just fine. I’ve also tried reinstalling visual studio code.

I’ve tried on a couple different boards and removed them from my custom board and it always works with the Arduino serial monitor and never with the PlatformIO one. Is there some setting that I am forgetting?

Here is what I see in the terminal. Maybe 1 in 10 times half a line shows up when I first start it and then nothing:

--- Terminal on COM7 | 9600 8-N-1
--- Available filters and text transformations: colorize, debug, default, direct, esp8266_exception_decoder, hexlify, log2file, nocontrol, printable, send_on_enter, time
--- More details at https://bit.ly/pio-monitor-filters
--- Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H

Here is my platformio.ini

[env:esp12e]
platform = espressif8266
board = esp12e
framework = arduino
monitor_speed = 9600
monitor_port = COM7
upload_speed = 921600
upload_port = COM7
lib_deps = adafruit/Adafruit MCP23017 Arduino Library@^2.3.0

Here is my blink code where I was going to start implementing an IO expander (until I ran into issues with the serial monitor)

#include <Arduino.h>
#include <Adafruit_MCP23X17.h>
#include <Adafruit_MCP23X08.h>
#include <Adafruit_MCP23XXX.h>

#define LED_PASS_B1 16

#define SW_AUTO 14
#define SW_MAN  12

// Adafruit_MCP23X17 mcp;

void setup() {
  Serial.begin(9600);
  Serial.println("LED Array Jig Starting...");
  // if(!mcp.begin_I2C()) {
  //   Serial.println("Error. Can't connect to IO Expander");
  //   while(1); 
  // }

  // mcp.pinMode(0, OUTPUT);
  // mcp.writeGPIOA(0);

  pinMode(LED_PASS_B1, OUTPUT);

  pinMode(SW_AUTO,  INPUT);
  pinMode(SW_MAN,   INPUT);
}

void loop() {
  if( digitalRead(SW_AUTO) )
  {
    Serial.println("Button pressed");
    digitalWrite(LED_PASS_B1, 1);
  } else {
    digitalWrite(LED_PASS_B1, 0);
  }
}
2

If the sketch works for as long as you don’t open the serial monitor, but stops the moment you open it, hen you have misconfigured DTR/RTS lines and that causes the chip to held in reset.

Please try all available combinations from here.

3

Ahhh that’s super helpful, I’ve got it working now. Thank you so much maxgerhardt!