Error writing to I2C bus

Surya

In another script, I'm trying to upload 'ENV' sensor readings to AWS IoT Core using MQTT.

I've connected AtomPoE Base to AtomS3 for Ethernet, using the port behind AtomS3, and attached the ENV sensor to the Grove port. Both AtomPoE and the ENV sensor use different ports. However, when I use MQTT_Client.connect(), it triggers a similar crash in the ENV sensor. Without the connection, the sensor works perfectly fine.

Any advice on how to address this issue would be greatly appreciated!

#include <M5AtomS3.h>
#include <M5Unified.h>
#include <SPI.h>
#include <SSLClient.h>
#include <M5_Ethernet.h>
#include <PubSubClient.h>
#include "certificates.h"
#include <ArduinoJson.h>
#include <SensirionI2CSht4x.h>
#include <Adafruit_BMP280.h>
#include <Adafruit_Sensor.h>

#define SCK 5
#define MISO 7
#define MOSI 8
#define CS 6

Adafruit_BMP280 bmp;
SensirionI2CSht4x sht4x;

float temperature, pressure, humidity;

// The MQTT topics that this device should publish/subscribe
#define AWS_IOT_PUBLISH_TOPIC "AtomS3/env"
#define AWS_IOT_SUBSCRIBE_TOPIC "AtomS3/msg"

const char my_cert[] = "-----BEGIN CERTIFICATE-----\n"
                       "MIIDWjCCAkKg...\n"
                       "-----END CERTIFICATE-----\n";
const char my_key[] = "-----BEGIN RSA PRIVATE KEY-----\n"
                      "MIIEowIBAAKCAQEAk...\n"
                      "-----END RSA PRIVATE KEY-----\n";

SSLClientParameters mTLS = SSLClientParameters::fromPEM(my_cert, sizeof my_cert, my_key, sizeof my_key);

byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x89};

const char *mqttServer = "a1pexxx.amazonaws.com";

void callback(char *topic, byte *payload, unsigned int length)
{
    Serial.print("Message arrived [");
    Serial.print(topic);
    Serial.print("] ");
    for (int i = 0; i < length; i++)
    {
        Serial.print((char)payload[i]);
    }
    Serial.println();
}

EthernetClient ethClient;
SSLClient ethClientSSL(ethClient, TAs, (size_t)TAs_NUM, 2);
PubSubClient client(mqttServer, 8883, callback, ethClientSSL);

void reconnect()
{
    // Loop until we're reconnected
    while (!client.connected())
    {
        Serial.print("Attempting MQTT connection...");
        // Attempt to connect
        if (client.connect("arduinoClient"))
        {
            Serial.println("connected");
            // Once connected, publish an announcement...
            client.publish("outTopic", "hello world");
            // ... and resubscribe
            client.subscribe("ENV_TEST");
        }
        else
        {
            Serial.print("failed, rc=");
            Serial.print(client.state());
            Serial.println(" try again in 5 seconds");
            // Wait 5 seconds before retrying
            delay(5000);
        }
    }
}

void publishMessage()
{
    StaticJsonDocument<200> doc;
    doc["temperature"] = temperature;
    doc["humidity"] = humidity;
    doc["pressure"] = pressure;
    char jsonBuffer[512];
    serializeJson(doc, jsonBuffer); // print to client

    client.publish(AWS_IOT_PUBLISH_TOPIC, jsonBuffer);
}

void setup()
{
    M5.begin();
    M5.Power.begin(); // Init power
    M5.Lcd.setTextSize(2);
    M5.Lcd.println("Init..");
    SPI.begin(SCK, MISO, MOSI, -1);
    Wire.begin();
    Serial.begin(115200);
    while (!bmp.begin(BMP280_ADDRESS_ALT))
    {
        M5.Lcd.println("Could not find a valid BMP280 sensor, check wiring!");
        Serial.println(F("BMP280 fail"));
    }
    M5.Lcd.clear(); // Clear the screen.
    Serial.println(F("BMP280 test"));

    uint16_t error;
    char errorMessage[256];

    sht4x.begin(Wire, SHT40_I2C_ADDR_44);

    bmp.setSampling(Adafruit_BMP280::MODE_NORMAL,
                    Adafruit_BMP280::SAMPLING_X2,
                    Adafruit_BMP280::SAMPLING_X16,
                    Adafruit_BMP280::FILTER_X16,
                    Adafruit_BMP280::STANDBY_MS_500);

    Ethernet.init(CS);
    M5.Lcd.println("Connecting ethernet...");
    while (Ethernet.begin(mac) != 1)
    {
        Serial.println("Error getting IP address via DHCP, trying again...");
        delay(1000);
    }

    // Check for Ethernet hardware present
    if (Ethernet.hardwareStatus() == EthernetNoHardware)
    {
        Serial.println(
            "Ethernet shield was not found.  Sorry, can't run without "
            "hardware. :(");
        while (true)
        {
            delay(1); // do nothing, no point running without Ethernet hardware
        }
    }
    if (Ethernet.linkStatus() == LinkOFF)
    {
        Serial.println("Ethernet cable is not connected.");
    }
    delay(5000);

    ethClientSSL.setMutualAuthParams(mTLS);
    Serial.println(client.connect("ENV_TEST"));
}

void loop()
{
    if (!client.connected())
    {
        M5.Lcd.println("reconnecting...");
        reconnect();
    }
    else
    {
        SPI.begin(SCK, MISO, MOSI, -1);
        uint16_t error;
        char errorMessage[256];

        pressure = bmp.readPressure();
        error = sht4x.measureHighPrecision(temperature, humidity);

        if (error)
        {
            Serial.print("Error trying to execute measureHighPrecision(): ");
            errorToString(error, errorMessage, 256);
            Serial.println(errorMessage);
        }
        else
        {
            Serial.print("Temperature:");
            Serial.print(temperature);
            Serial.print("\t");
            Serial.print("Humidity:");
            Serial.println(humidity);
        }
        M5.Lcd.clear();
        M5.Lcd.setCursor(0, 0); // Set the cursor to (0,0)
        M5.Lcd.printf("T:%2.0f", temperature);
        M5.Lcd.setCursor(0, 20);
        M5.Lcd.printf("P:%2.0f", pressure);
        M5.Lcd.setCursor(0, 40);
        M5.Lcd.print("H:");
        M5.Lcd.print(humidity);
        M5.Lcd.print("%");

        delay(100);
        publishMessage();
    }
    client.loop();
    delay(10000);
}

teastain

@surya As @felmue says, they cannot both run from the Grove port.
The DS18B20 is completely different and incompatible with I2C.
It only needs 1 wire, so you may use the Power and Ground from the Grove and connect the DS18B20 signal pin to any-other-pin on the bottom of the AtomS3.

Surya

@teastain Thanks for the clarification!

Yeah, I understood that these sensors likely use different communication protocols. Also, I attempted to use a different GPIO pin for the DS18B20, and it worked perfectly for me.

Now, my only concern is my second script. Here, I'm using different ports for the ENV sensor and AtomPoE base in AtomS3. However, when I connect with the MQTT client, it breaks the ENV sensor's communication. Any advice is greatly appreciated!

0_1708666315261_d62524c3-fdf8-4e9f-bec5-8de0ac674050-image.png

ajb2k3

Have you check out my example in the Project zone as the MQTT has to be in a specific place in the code.

Surya

@ajb2k3

I appreciate your input! Could you please share the link or specify the topic name related to the example you mentioned in the Project zone? I'm interested in diving deeper.

ajb2k3

@surya https://uiflow2.m5stack.com/?pkey=c1c7d2ca888b497aab31505e1091adc6

Another member on the forum was having difficulties so I shared the code I use for sending data over MQTT to my private server hosted on a CM4Stack.

Surya

@ajb2k3

Thank you so much for sharing your work!

Earlier, I successfully sent data over MQTT to AWS IoT Core in UIFlow2. However, in UIFlow2, I couldn't find a way to establish a (DHCP) Ethernet connection to AtomS3 using AtomPoE Base. That's why I decide to develop the code using PlatformIO. Do you have any reference Micropython script for an Ethernet connection?

ajb2k3

Alas no as I don’t have one of those

felmue

Hello @Surya

looking at your Arduino code I think a possible issue is the long delay of 10 seconds in loop() blocking client.loop(). You need to get rid of the long delay. How to periodically execute code without blocking is shown here.

Thanks
Felix

Surya

Hello @felmue

I have already attempted a short delay, but unfortunately, that doesn't work for me. As for periodic code execution, I will give it a try.

Thanks
Surya

Surya

Oops, I forgot to share the error message. Here it is
0_1708690342175_ed5ae410-5ec1-4881-a73d-af18d629b2f6-image.png

felmue

Hello @Surya

after long hours of searching and debugging I found the reason why I2C would fail. It starts to fail as soon as SSL is invoked. The SSL library uses an analog GPIO as input for its random seed. And in your code you used GPIO2 which is one of M5AtomS3 Groove GPIOs.

So to get rid of the I2C error try changing the GPIO used for random seed to GPIO10.

//SSLClient ethClientSSL(ethClient, TAs, (size_t)TAs_NUM, 2);
SSLClient ethClientSSL(ethClient, TAs, (size_t)TAs_NUM, GPIO_NUM_10);

Thanks
Felix

teastain

@felmue Laughed out loud, in brotherhood.
Great job!

Surya

Hello @felmue

I implemented the change using GPIO10 for the random seed, and the I2C issue seems to be resolved. Your help is greatly appreciated!

Thank you for your fix!
Surya