Serial not Transmitting on Wake Up
Posted: Wed Mar 03, 2021 10:35 pmHello there, noob to the forums and fairly so with the ESP8266. I have a project that uses I2c for the OLED display and talks to another device via serial (pins 3-RX, 1-TX). I had it all working, or so I thought, and found that on "power up" everything ran great. Then the ESP goes to DeepSleep and when it wakes up it just "might" send commands out the Serial but it also may not.
So then I started from the beginning and skinnied the code down to reduce variables at potential play in the matter. When I did the following it works 100% of the time. (working = Serial.print("I'm awake"), turn LED on, sleeps for 5 seconds, goes to deep sleep, wakes up with the click of a button which sends a low to RST and repeats as expected). Here is the quite simple code, that again seems to work 100% of the time.
BUT when I add in the display code for the OLED the following happens...
1 - it always works on power up (boot)
2 - first or second wake might also work
3 - never works again but the code never errors, it simply acts like it transmitted and moved to next line in code. for instance, the display will load all of the heading images and then the "Hello World" for 5 seconds and then back to deep sleep. But nothing is sent to the Serial Monitor in the code below. (or the device in my project code which is simply sending a "Serial.print('O');"
As I just mentioned, I validated this with the Serial Terminal and was shocked (not sure why) I saw this exact same behavior there too. Here is the code for what does not work as desired.
Have any of you ever seen this before? I have also tried using SoftwareSerial in case it was an error in the standard serial library but no dice, same result. Please do let me know your thoughts. thanks,
So then I started from the beginning and skinnied the code down to reduce variables at potential play in the matter. When I did the following it works 100% of the time. (working = Serial.print("I'm awake"), turn LED on, sleeps for 5 seconds, goes to deep sleep, wakes up with the click of a button which sends a low to RST and repeats as expected). Here is the quite simple code, that again seems to work 100% of the time.
Code: Select all
#define LED 2 //Define connection of LED
void setup() {
Serial.begin(115200);
Serial.setTimeout(2000);
while(!Serial){}
Serial.println("I'm awake now!);
pinMode(LED, OUTPUT); // Initialize the LED_BUILTIN pin as an output
digitalWrite(LED, LOW); // Turn the LED on (Note that LOW is the voltage level
delay(5000);
ESP.deepSleep(0);
}
void loop() {
}BUT when I add in the display code for the OLED the following happens...
1 - it always works on power up (boot)
2 - first or second wake might also work
3 - never works again but the code never errors, it simply acts like it transmitted and moved to next line in code. for instance, the display will load all of the heading images and then the "Hello World" for 5 seconds and then back to deep sleep. But nothing is sent to the Serial Monitor in the code below. (or the device in my project code which is simply sending a "Serial.print('O');"
As I just mentioned, I validated this with the Serial Terminal and was shocked (not sure why) I saw this exact same behavior there too. Here is the code for what does not work as desired.
Code: Select all
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define LED 2 //Define connection of LED
// OLED Display
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height, in pixels
#define OLED_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
#define CHARGE_AREA_START_X 20
#define CHARGE_AREA_START_Y 18
#define CHARGE_AREA_WIDTH 83
#define CHARGE_AREA_HEIGHT 28
// 'FullBat', 25x8px
const unsigned char fullBat [] PROGMEM = {
0x1f, 0xff, 0xff, 0x80, 0x18, 0x00, 0x01, 0x80, 0xfb, 0xff, 0xfd, 0x80, 0xfb, 0xff, 0xfd, 0x80,
0xfb, 0xff, 0xfd, 0x80, 0xfb, 0xff, 0xfd, 0x80, 0x18, 0x00, 0x01, 0x80, 0x1f, 0xff, 0xff, 0x80
};
// 'wifi', 15x10px
const unsigned char wifi [] PROGMEM = {
0x00, 0x00, 0x3f, 0xf8, 0x7f, 0xfc, 0x70, 0x1c, 0x07, 0xe0, 0x1f, 0xf0, 0x0c, 0x60, 0x01, 0x00,
0x03, 0x80, 0x01, 0x00
};
void setup() {
// Serial Setup
Serial.begin(115200);
Serial.setTimeout(2000);
while(!Serial) { }
Serial.println("I'm awake now");
// OLED Setup
display.setRotation(2); // Set rotation
if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x32
for(;;); // Don't proceed, loop forever
}
DrawScreen();
// Turn the LED on
pinMode(LED, OUTPUT);
digitalWrite(LED, LOW);
delay(5000);
// Going to Deep Sleep
Serial.println("I'm shutting down now");
display.clearDisplay();
display.display();
ESP.deepSleep(0);
}
void loop() {
}
void DrawScreen(void) {
display.clearDisplay();
display.setTextColor(SSD1306_WHITE);
display.drawBitmap(0,0,wifi,15,10,1); // Wifi (18,12)
display.drawBitmap(87,0,fullBat,25,8,1); // Battery
display.setCursor(0, 16);
display.setTextSize(.5);
display.print("Hello World");
display.display();
}
Have any of you ever seen this before? I have also tried using SoftwareSerial in case it was an error in the standard serial library but no dice, same result. Please do let me know your thoughts. thanks,