ESP8266 seems to be killing a while loop

Question

When i was testing out a program I found a strange behavior of esp8266

It seems to get out of a while loop even when there's no option of getting out on code

I don't know if these are related but here's the code (the program is just two different visual patterns of leds toggled by a button)

#define led1 D0
#define led2 D1
#define led3 D2
#define led4 D3
#define button D7
unsigned long pressedButton;
bool change = 0;
unsigned long previousTime;
unsigned int difference;
void setup() {
 pinMode(led1, OUTPUT);
 pinMode(led2, OUTPUT);
 pinMode(led3, OUTPUT);
 pinMode(led4, OUTPUT);
 pinMode(button, INPUT_PULLUP);
}
void loop(){
 digitalWrite(led1, LOW);
 digitalWrite(led2, LOW);
 digitalWrite(led3, LOW); //when the while loop change, this should delete interference
 digitalWrite(led4, LOW);
 previousTime = millis();
 
 while (!change){ //default visual pattern of leds
 difference = millis()-previousTime;
 
 if (!digitalRead(led1) && difference>=200){
 digitalWrite(led1, HIGH);
 }
 if (!digitalRead(led2) && difference>=400){
 digitalWrite(led2, HIGH);
 }
 if (!digitalRead(led3) && difference>=600){
 digitalWrite(led3, HIGH);
 }
 if (!digitalRead(led4) && difference>=800){ //after here, all the leds should be HIGH
 digitalWrite(led4, HIGH);
 }
 if (digitalRead(led4) && difference>=1000){
 digitalWrite(led4, LOW);
 }
 if (digitalRead(led3) && difference>=1200){
 digitalWrite(led3, LOW);
 }
 if (digitalRead(led2) && difference>=1400){
 digitalWrite(led2, LOW);
 }
 if (digitalRead(led1) && difference>=1600){ //after here, all the leds should be LOW
 digitalWrite(led1, LOW);
 previousTime = millis();
 }
 
 if (!digitalRead(button) && millis()-pressedButton>200){ //check if button was pressed to break while loop
 pressedButton = millis();
 break;
 }
 }
 
 while (change){ //alternative of visual pattern of leds
 difference = millis()-previousTime;
 
 if (!digitalRead(led1) && difference>=200){
 digitalWrite(led1, HIGH);
 digitalWrite(led4, HIGH);
 digitalWrite(led2, LOW);
 digitalWrite(led3, LOW);
 }
 if (digitalRead(led1) && difference>=400){
 digitalWrite(led1, LOW);
 digitalWrite(led4, LOW);
 digitalWrite(led2, HIGH);
 digitalWrite(led3, HIGH);
 previousTime = millis();
 }
 //if (!digitalRead(button) && millis()-pressedButton>=200){ //check if button was pressed to break while loop
 // pressedButton = millis();
 // break;
 //}
 }
 
 change = !change; //after a break in one of the while loops, this will make the program go to the other while loop
 }

Is there something wrong with the code? Here is a link of a video of the behavior for more details https://drive.google.com/file/d/1822MHNGQn-A2-HGHhRXz_8xydz-wM4Ha/view?usp=sharing

• Delta_G: You can't trap an ESP in a while loop like that. There are things it needs to get back to main and do between loops. Instead, let the loop function be your loop. Make the while statements if statements and where you have break, that's where you change the change variable. Put the code at the top in an if statement that checks to see if change has changed.
• Nick Gammon: @Delta_G Please make an answer and not a comment.
• the busybee: Concerning your LED issue: Even if it happens with your current sketch, please post a separate question for it. When you do, please add a schematic of your circuit.
• Delta_G: @NickGammon. Done.
• tatu101: @the busybee all right I didn't know the problems were not related. Like that? arduino.stackexchange.com/questions/93807/…

Answer 1

You can't trap an ESP in a while loop like that. There are things it needs to get back to main and do between loops. Instead, let the loop function be your loop. Make the while statements if statements and where you have break, that's where you change the change variable. Put the code at the top in an if statement that checks to see if change has changed.

#define led1 D0
#define led2 D1
#define led3 D2
#define led4 D3
#define button D7
unsigned long pressedButton;
bool change = 0;
bool oldChange = 1;
unsigned long previousTime;
unsigned int difference;
void setup() {
 pinMode(led1, OUTPUT);
 pinMode(led2, OUTPUT);
 pinMode(led3, OUTPUT);
 pinMode(led4, OUTPUT);
 pinMode(button, INPUT_PULLUP);
}
void loop() {
 if (change != oldChange) {
 digitalWrite(led1, LOW);
 digitalWrite(led2, LOW);
 digitalWrite(led3, LOW); //when the while loop change, this should delete interference
 digitalWrite(led4, LOW);
 previousTime = millis();
 oldChange = change;
 }
 if (!change) { //default visual pattern of leds
 difference = millis() - previousTime;
 if (!digitalRead(led1) && difference >= 200) {
 digitalWrite(led1, HIGH);
 }
 if (!digitalRead(led2) && difference >= 400) {
 digitalWrite(led2, HIGH);
 }
 if (!digitalRead(led3) && difference >= 600) {
 digitalWrite(led3, HIGH);
 }
 if (!digitalRead(led4) && difference >= 800) { //after here, all the leds should be HIGH
 digitalWrite(led4, HIGH);
 }
 if (digitalRead(led4) && difference >= 1000) {
 digitalWrite(led4, LOW);
 }
 if (digitalRead(led3) && difference >= 1200) {
 digitalWrite(led3, LOW);
 }
 if (digitalRead(led2) && difference >= 1400) {
 digitalWrite(led2, LOW);
 }
 if (digitalRead(led1) && difference >= 1600) { //after here, all the leds should be LOW
 digitalWrite(led1, LOW);
 previousTime = millis();
 }
 if (!digitalRead(button) && millis() - pressedButton > 200) { //check if button was pressed to break while loop
 pressedButton = millis();
 change = true;
 }
 }
 if (change) { //alternative of visual pattern of leds
 difference = millis() - previousTime;
 if (!digitalRead(led1) && difference >= 200) {
 digitalWrite(led1, HIGH);
 digitalWrite(led4, HIGH);
 digitalWrite(led2, LOW);
 digitalWrite(led3, LOW);
 }
 if (digitalRead(led1) && difference >= 400) {
 digitalWrite(led1, LOW);
 digitalWrite(led4, LOW);
 digitalWrite(led2, HIGH);
 digitalWrite(led3, HIGH);
 previousTime = millis();
 }
 }
 change = false 
}

• tatu101: Thank you! That resolved the unwanted break on the second pattern. But what is the reason for the while loop not working inside another loop?
• Delta_G: The loop function is called repeatedly from main(). There are other things in main() that have to happen in between calls to loop. You can't trap execution inside loop. You have to let loop exit once in a while or call yield or delay(0). In your case, you didn't need a while loop since loop is already a loop.