@mati It seems it's not available for Sticks and Atoms.

Is the expected behavior from the server, keep the last received value.

@stoni99 I think you must use DARKGREY or LIGHTGREY.
see this

@creakygate same here, also greyed for atoms. No solution that I know.

With this code:

#include <M5Atom.h>

void setup(){
       M5.begin(true, false, true);    //Initialize M5Atom. 
       delay(50);   //Delayed 50ms. 
       M5.dis.fillpix(0xFFFFFF);
       delay(10000);
       M5.dis.clear();
}

void loop(){
}

I've got 24 leds on, the last one off , but if I change the
#define NUM_LEDS 25 to 26 in
.pio/libdeps/m5stack-atom/M5Atom/src/utility/LED_DisPlay.h
I've got 25 leds on
Is it a known bug in the atom lib?

@mlindholm would you share the link to that blog post?. Thanks.

@felmue thanks, now it compiles and uploads to the atom. But it does not work. I have also changed the ports in CBACK_DRIVER.cpp to match the ones of the atom-mate, from

Wire.begin(0, 26);

to

Wire.begin(19,22);

but no luck.

I¡m trying to run a couple of servos with atom lite, using the atom-mate and the cback-driver for m5stick. Using platformio, I've copied CBACK_DRIVER.h and CBACK_DRIVER.cpp to the include dir in the project, modified the obvious #include <M5Atom.h>, and with this code:

#include <M5Atom.h>
#include "CBACK_DRIVER.h"

bool flag = true;

CBACK_DRIVER Driver;
int C_BLACK = 0x000000;
int C_WHITE = 0xffffff;
int C_RED = 0xff0000;
int C_GREEN = 0x00ff00;
int C_BLUE = 0x0000ff;


void setup() {
        M5.begin(true, false, true);
        // let's check the atom is ok
        delay(50);
        M5.dis.drawpix(0, C_GREEN); // green
        delay(1000);
        M5.dis.drawpix(0, C_BLACK); // black
        Serial.begin(115200);
                Driver.Init();
                delay(1000);
                Serial.println("C Back Driver Test...");

}
void loop() {
        if(M5.Btn.wasPressed()){
                flag = !flag;
                Serial.println("toggle flag value");
        }
        if(flag){
                for(int i=1; i<=4;i++){
                        Driver.SetServoAngle(i,90);
                        Serial.println("servo 90");
                        // Driver.ReadServoPulse(i,1500);
                }
                Driver.SetOutput(1);
        }else{
                for(int i=1; i<=4;i++){
                        Driver.SetServoAngle(i,120);
                        Serial.println("servo 120");
                        // Driver.ReadServoPulse(i,2000);
                }
                Driver.SetOutput(0);
        }
        Serial.print("PortB ADC: ");
        Serial.println(Driver.ReadADC());
        M5.update();
}

I get this error:

Building in release mode
Linking .pio/build/m5stack-atom/firmware.elf
.pio/build/m5stack-atom/src/main.cpp.o:(.literal._Z5setupv+0x2c): undefined reference to `CBACK_DRIVER::Init()'
.pio/build/m5stack-atom/src/main.cpp.o:(.literal._Z4loopv+0x18): undefined reference to `CBACK_DRIVER::SetServoAngle(unsigned char, unsigned char)'
.pio/build/m5stack-atom/src/main.cpp.o:(.literal._Z4loopv+0x1c): undefined reference to `CBACK_DRIVER::SetOutput(unsigned char)'
.pio/build/m5stack-atom/src/main.cpp.o:(.literal._Z4loopv+0x20): undefined reference to `CBACK_DRIVER::ReadADC()'
.pio/build/m5stack-atom/src/main.cpp.o: In function `setup()':
/home/benalb/Projects/m5atom/cback/src/main.cpp:22: undefined reference to `CBACK_DRIVER::Init()'
.pio/build/m5stack-atom/src/main.cpp.o: In function `loop()':
/home/benalb/Projects/m5atom/cback/src/main.cpp:36: undefined reference to `CBACK_DRIVER::SetServoAngle(unsigned char, unsigned char)'
/home/benalb/Projects/m5atom/cback/src/main.cpp:40: undefined reference to `CBACK_DRIVER::SetServoAngle(unsigned char, unsigned char)'
/home/benalb/Projects/m5atom/cback/src/main.cpp:44: undefined reference to `CBACK_DRIVER::SetOutput(unsigned char)'
/home/benalb/Projects/m5atom/cback/src/main.cpp:47: undefined reference to `CBACK_DRIVER::ReadADC()'
collect2: error: ld returned 1 exit status
*** [.pio/build/m5stack-atom/firmware.elf] Error 1
========================================================= [FAILED] Took 13.90 seconds =========================================================

any ideas?

@felmue Thank you very much for the solution and the explanation. It now works,

As the subject says, I have copied the example code for esp-now on esp32 from randomnerdtutorials to comunicate a stickC with an Atom Lite. If the atom is off,the code works ok, but if the atom is on, the message is sent once, and then, the stickC reboots, in a loop, send message, reboot, send message, reboot.

/*
 * based on https://randomnerdtutorials.com/esp-now-esp32-arduino-ide/
 */
#include <M5StickC.h>
#include <WiFi.h>
#include <esp_now.h>

// wifi settings
const char* ssid = "cositas_electronicas";

IPAddress local_IP(192, 168, 0, 101);
IPAddress gateway(192, 168, 0, 1);
IPAddress subnet(255, 255, 0, 0);
IPAddress primaryDNS(1, 1, 1, 1);   //optional
IPAddress secondaryDNS(9, 9, 9, 9); //optional

// esp now
// receiver mac address
uint8_t broadcastAddress[] = {0x24, 0xA1, 0x60, 0x46, 0xF1, 0x70};

// structure to send data, must match receiver structure
typedef struct struct_message {
        char a[32];
        int b;
} struct_message;

// create a struct_message called myData
struct_message myData;

// callback when data is sent
void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {
        M5.Lcd.fillScreen(BLACK);
        M5.Lcd.setCursor(0, 20);
        M5.Lcd.println("Last Pkg send status");
        M5.Lcd.println(status == ESP_NOW_SEND_SUCCESS ? "Delivery Success" : "Delivery Fail");
}
void setup() {
        M5.begin();
        Serial.begin(115200);
        Serial.println("starting....");

        WiFi.mode(WIFI_AP_STA);
        // Configures static IP address
        if (!WiFi.config(local_IP, gateway, subnet, primaryDNS, secondaryDNS)) {
                Serial.println("STA Failed to configure");
        }

        // Connect to Wi-Fi network with SSID
        M5.Lcd.fillScreen(BLACK);
        M5.Lcd.setTextColor(GREEN , BLACK);
        M5.Lcd.setRotation(3);
        M5.Lcd.setCursor(0, 20);
        M5.Lcd.println("Connecting to ");
        M5.Lcd.println(ssid);
        WiFi.begin(ssid);
        while (WiFi.status() != WL_CONNECTED) {
                delay(500);
                M5.Lcd.print(".");
        }

        // Print local IP address
        M5.Lcd.fillScreen(BLACK);
        M5.Lcd.setCursor(0, 20);
        M5.Lcd.println("WiFi connected.");
        M5.Lcd.println("IP address: ");
        M5.Lcd.println(WiFi.localIP());
        delay(1000);
        M5.Lcd.fillScreen(BLACK);
        Serial.println(WiFi.macAddress());
        // init esp-now
        if (esp_now_init() != ESP_OK) {
                Serial.println("Error initializing ESP-NOW");
                return;
        }
        // Once ESPNow is successfully Init, we will register for Send CB to
        // get the status of Trasnmitted packet
        esp_now_register_send_cb(OnDataSent);

        // Register peer
        esp_now_peer_info_t peerInfo;
        memcpy(peerInfo.peer_addr, broadcastAddress, 6);
        peerInfo.channel = 0;  
        peerInfo.encrypt = false;
        // Add peer        
        if (esp_now_add_peer(&peerInfo) != ESP_OK) {
                M5.Lcd.fillScreen(BLACK);
                M5.Lcd.setCursor(0, 20);
                M5.Lcd.println("Failed to add peer");
                return;
        }
}

void loop() {
        // Set values to send
        strcpy(myData.a, "This is a char");
        myData.b = random(1, 10);
        // Send message via ESP-NOW
        esp_err_t result = esp_now_send(broadcastAddress, (uint8_t *) &myData, sizeof(myData));

        if (result == ESP_OK) {
                M5.Lcd.fillScreen(BLACK);
                M5.Lcd.setCursor(0, 20);
                M5.Lcd.println("Sent with success");
        }
        else {
                M5.Lcd.fillScreen(BLACK);
                M5.Lcd.setCursor(0, 20);
                M5.Lcd.println("Error sending the data");
        }
        delay(2000);
}

In the serial monitor I get this:

M5StickC initializing...OK
starting....
24:A1:60:45:B2:44

ELF file SHA256: 0000000000000000

Backtrace: 0x40088e68:0x3ffbf810 0x400890e5:0x3ffbf830 0x4012f684:0x3ffbf850 0x40086f65:0x3ffbf870 0x400d1bf8:0x3ffb5830 0x400d26fb:0x3ffb5850 0x4014565d:0x3ffb5880 0x400d06c5:0x3ffb58a0 0x40133f75:0x3ffb58c0 0x401028ef:0x3ffb58e0 0x40104b6e:0x3ffb5910 0x4008a0f6:0x3ffb5940
  #0  0x40088e68:0x3ffbf810 in invoke_abort at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/esp32/panic.c:715
  #1  0x400890e5:0x3ffbf830 in abort at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/esp32/panic.c:715
  #2  0x4012f684:0x3ffbf850 in task_wdt_isr at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/esp32/task_wdt.c:252
  #3  0x40086f65:0x3ffbf870 in _xt_lowint1 at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/freertos/xtensa_vectors.S:1154
  #4  0x400d1bf8:0x3ffb5830 in TFT_eSPI::setWindow(int, int, int, int) at .pio/libdeps/m5stick-c/M5StickC/src/utility/In_eSPI.cpp:5995
  #5  0x400d26fb:0x3ffb5850 in TFT_eSPI::fillRect(int, int, int, int, unsigned int) at .pio/libdeps/m5stick-c/M5StickC/src/utility/In_eSPI.cpp:5995
  #6  0x4014565d:0x3ffb5880 in TFT_eSPI::fillScreen(unsigned int) at .pio/libdeps/m5stick-c/M5StickC/src/utility/In_eSPI.cpp:5995
  #7  0x400d06c5:0x3ffb58a0 in OnDataSent(unsigned char const*, esp_now_send_status_t) at src/main.cpp:32
  #8  0x40133f75:0x3ffb58c0 in esp_now_add_peer at ??:?
  #9  0x401028ef:0x3ffb58e0 in ppProcTxDone at ??:?
  #10 0x40104b6e:0x3ffb5910 in ppTask at ??:?
  #11 0x4008a0f6:0x3ffb5940 in vPortTaskWrapper at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/freertos/port.c:355 (discriminator 1)

Rebooting...
M5StickC initializing...OK
starting....
24:A1:60:45:B2:44

This happens in two different stickC, using platformio in linux. Any ideas?

@mati It seems it's not available for Sticks and Atoms.