How to make a smaller .bin?

aezero

Hi all,

I'm going to be deploying a bunch of M5Stack core units with LTE modems. I have been writing a small firmware that I can push to them OTA in case a unit gets lost or stolen. This way, the original firmware if replaced with a "if found, return to..." message. It's very simple but still compiles to 346KB, which does not OTA very quickly (Carrier problem. I have another thread that explains why.). I'd really like to get this to a smaller size, if I can. Is there a way to either optimize the compiler to shed code that it doesn't use (ie. wifi, etc), or can I manually trim down the M5stack library?

Thanks!!

#define SerialMon Serial

void debug(String msg) {
    SerialMon.print(msg);
    M5.Lcd.print(msg);
}

void debugln(String msg) {
    SerialMon.println(msg);
    M5.Lcd.println(msg);
}

void setup() {
    M5.begin();
    SerialMon.begin(115200);
    M5.Lcd.clear(TFT_BLACK);
    M5.Lcd.setTextSize(3);
    M5.Lcd.setTextColor(TFT_WHITE, TFT_BLACK);
    debugln(F("If found, call"));
    debugln(F("xxxxxxxx"));
    debugln(F("xxxxxxxxxxxxx"));
    debugln(F(""));
    debugln(F("or return to"));
    debugln(F("xxxxxxxxxx"));
    debugln(F("xxxxxxxx"));
    debugln(F("xxxxxxxxxxxx"));
    debugln(F("xxxxxxxxxxxx"));
    }

void loop() {
}

flypeek

https://github.com/Bodmer/TFT_eSPI
compiles to 293KB

#define SerialMon Serial
#include <TFT_eSPI.h>
TFT_eSPI Tft = TFT_eSPI();
void debug(String msg) {
    SerialMon.print(msg);
    Tft.print(msg);
}

void debugln(String msg) {
    SerialMon.println(msg);
    Tft.println(msg);
}

void setup() {
    SerialMon.begin(115200);
    Tft.init();
    Tft.fillScreen(TFT_BLACK);
    Tft.setTextSize(3);
    Tft.setTextColor(TFT_WHITE, TFT_BLACK);
    debugln(F("If found, call"));
    debugln(F("xxxxxxxx"));
    debugln(F("xxxxxxxxxxxxx"));
    debugln(F(""));
    debugln(F("or return to"));
    debugln(F("xxxxxxxxxx"));
    debugln(F("xxxxxxxx"));
    debugln(F("xxxxxxxxxxxx"));
    debugln(F("xxxxxxxxxxxx"));
    }

void loop() {
}

aezero

That helps! Thank you!

I'm going to drop the SerialMon stuff too. I only added it just in case I had a unit with a faulty screen, but then I realized that if the screen were faulty, no one would see the message to bring it back to me. And why would I want a unit with a faulty screen? LOL!

aezero

@flypeek It definitely compiles smaller! I got it down to around 250KB with the SerialMon disabled. The only issue I have is that it doesn't light up the backlight on the screen. I can see the text is there if I hold up a flashlight to it. Any idea how to light it up? I've been doing some searching, and it doesn't look like it's a simple HIGH/LOW sent to pin 32. The M5Stack.Lcd library says it's PWM controlled.

Thanks!

flypeek

1.M5Stack.Lcd use Brightness (0: Off - 255:Full)
https://github.com/m5stack/m5-docs/blob/master/docs/en/api/lcd.md#setbrightness

https://github.com/Bodmer/TFT_eSPI#tips
or 2.edit User_Setup.h or rename

// ########################################################
// Section 2. Define the pins that are used to interface with the display here
//#######################################################

// If a backlight control signal is available then define the TFT_BL pin in Section 2
// below. The backlight will be turned ON when tft.begin() is called, but the library
// needs to know if the LEDs are ON with the pin HIGH or LOW. If the LEDs are to be
// driven with a PWM signal or turned OFF/ON then this must be handled by the user
// sketch. e.g. with digitalWrite(TFT_BL, LOW);

#define TFT_BL   32            // LED back-light control pin
#define TFT_BACKLIGHT_ON HIGH  // Level to turn ON back-light (HIGH or LOW)