Use EspSoftwareSerial with AdafruitThermal library

Using Arduino Programming Questions
#1

Hi,
is there a way to use the AdafruitThermalLibrary with the softwareSerial of the ESP8266? I’m using a nodeMCU 1.0 board, but I’m having no luck making the library working on the ESP. I have tested a nearly identical code with an Arduino UNO and the same electrical setup and it worked.
The only electrical question that I have is if it’s fine to use RX and TX from 3.3V of the esp to 5V of the printer.

This is the code:

#include "Adafruit_Thermal.h"
#include <SoftwareSerial.h>
#include <ESP8266WiFi.h>
#include "adalogo.h"
#include "adaqrcode.h"

#define TX_PIN 6 // Arduino transmit  YELLOW WIRE  labeled RX on printer
#define RX_PIN 5 // Arduino receive   GREEN WIRE   labeled TX on printer

SoftwareSerial mySerial; // Declare SoftwareSerial obj first
Adafruit_Thermal printer(&mySerial);     // Pass addr to printer constructor

void setup() {
  pinMode(7, OUTPUT); digitalWrite(7, LOW);

  // NOTE: SOME PRINTERS NEED 9600 BAUD instead of 19200, check test page.
  mySerial.begin(9600, SWSERIAL_8N1, TX_PIN, RX_PIN, false, 256);
  //Serial1.begin(19200); // Use this instead if using hardware serial
  printer.begin();        // Init printer (same regardless of serial type)
  
  // Test inverse on & off
  printer.inverseOn();
  printer.println(F("Inverse ON"));
  printer.inverseOff();

  // Test character double-height on & off
  printer.doubleHeightOn();
  printer.println(F("Double Height ON"));
  printer.doubleHeightOff();

  // Set text justification (right, center, left) -- accepts 'L', 'C', 'R'
  printer.justify('R');
  printer.println(F("Right justified"));
  printer.justify('C');
  printer.println(F("Center justified"));
  printer.justify('L');
  printer.println(F("Left justified"));

  // Test more styles
  printer.boldOn();
  printer.println(F("Bold text"));
  printer.boldOff();

  printer.underlineOn();
  printer.println(F("Underlined text"));
  printer.underlineOff();

  printer.setSize('L');        // Set type size, accepts 'S', 'M', 'L'
  printer.println(F("Large"));
  printer.setSize('M');
  printer.println(F("Medium"));
  printer.setSize('S');
  printer.println(F("Small"));

  printer.justify('C');
  printer.println(F("normal\nline\nspacing"));
  printer.setLineHeight(50);
  printer.println(F("Taller\nline\nspacing"));
  printer.setLineHeight(); // Reset to default
  printer.justify('L');

  // Barcode examples:
  // CODE39 is the most common alphanumeric barcode:
  printer.printBarcode("ADAFRUT", CODE39);
  printer.setBarcodeHeight(100);
  // Print UPC line on product barcodes:
  printer.printBarcode("123456789123", UPC_A);

  // Print the 75x75 pixel logo in adalogo.h:
  printer.printBitmap(adalogo_width, adalogo_height, adalogo_data);

  // Print the 135x135 pixel QR code in adaqrcode.h:
  printer.printBitmap(adaqrcode_width, adaqrcode_height, adaqrcode_data);
  printer.println(F("Adafruit!"));
  printer.feed(2);

  printer.sleep();      // Tell printer to sleep
  delay(3000L);         // Sleep for 3 seconds
  printer.wake();       // MUST wake() before printing again, even if reset
  printer.setDefault(); // Restore printer to defaults
}

void loop() {
}

Many thanks!

#2

Ok just found the solution: I was using the wrong pins. The nodeMCU has dedicated pins for serial, in my case was D7 and D8. Just switched the cables and modified the code according and I was able to print.

#3