EnviroDIY

2020-10-29 at 11:28 AM #14739

Moderator

Alright, here’s something. I can’t promise it *works*, but I’d like to see the results.

#include <Arduino.h>
#include <Wire.h>

#define DEVICE_I2C_ADDRESS \
    0x4D  // I *think* this is the address it's using for itself
// https://github.com/NorthernWidget-Skunkworks/Project-Walrus/blob/b5d9cc1fdfe2cf16fb5048a1f9ff0b27253c3a94/Firmware/Walrus_I2C_5BA/Walrus_I2C_5BA.ino#L155


// A helpful union for flipping between bytes to longs
typedef union leFrame {
    byte     Byte[4];  // 4 bytes will occupy 4 bytes
    uint32_t uInt32;   // a single float occupies 4 bytes
} leFrame;

void setup() {
    Wire.begin();        // join i2c bus (address optional for master)
    Serial.begin(9600);  // start serial for output
    // NOTE:  Something may have to happen here to "start the thing up"
    // I can't tell if they intend that or not
}

void loop() {
    // It looks like the control register (0x00) is being set to 0x7F
    // (0b1111111) when values are being written (ie, values aren't ready) and
    // to 0x80 (0b10000000) when it's ready.
    // https://github.com/NorthernWidget-Skunkworks/Project-Walrus/blob/b5d9cc1fdfe2cf16fb5048a1f9ff0b27253c3a94/Firmware/Walrus_I2C_5BA/Walrus_I2C_5BA.ino#L242
    byte control_flag = 0x7f;
    while (control_flag == 0x7f) {
        Wire.beginTransmission(
            DEVICE_I2C_ADDRESS);  // select device with "beginTransmission()"
        Wire.write(0x00);         // select starting register with "write()"
        Wire.endTransmission();   // end write operation, as we just wanted to
        // select the starting register
        Wire.requestFrom(DEVICE_I2C_ADDRESS,
                         1);  // select number of bytes to get from the device
                              // (1 byte in this case)
        control_flag = Wire.read();  // read from the starting register
    }

    // We'll try reading all the registers at once sequentially instead of
    // reading one after the other
    // the registers are loaded starting on line 242:
    // https://github.com/NorthernWidget-Skunkworks/Project-Walrus/blob/master/Firmware/Walrus_I2C_5BA/Walrus_I2C_5BA.ino#L242
    Wire.beginTransmission(
        DEVICE_I2C_ADDRESS);  // select device with "beginTransmission()"
    Wire.write(0x02);         // select starting register with "write()"
    // the first data register is pressure starting in register 0x02
    Wire.endTransmission();  // end write operation, as we just wanted to select
                             // the starting register

    // select number of bytes to get from the device
    // + 4 for pressure in microbars (ie mbar*1000)
    // + 4 for temp0 - This is the temperature from the MCP9808 (*10000.0)
    // + 4 for temp1 - This is the temperature from the MS5803 (*10000.0)
    Wire.requestFrom(DEVICE_I2C_ADDRESS, 12);
    // We won't bother to read the next 8 bytes of unchanging sensor
    // information:
    // + 2 for model (uint16_t)
    // + 2 for group id (uint16_t)
    // + 2 for "INDID" ?dummy? (uint16_t)
    // + 2 for firmware id (uint16_t))

    // my helpful union
    leFrame fram;

    // NOTE:  may need to flop endinaness for the values.
    // if getting garbage, try switching all for loops to
    // 'for (int8_t i = 0; i<4; i++)'

    // get pressure from the first 4 bytes, reversing order/endianness
    for (int8_t i = 4; i; i--) { fram.Byte[i] = Wire.read(); }
    float pressure = fram.uInt32 / 1000;

    // get MCP9808 temp from the next 4 bytes, reversing order/endianness
    for (int8_t i = 4; i; i--) { fram.Byte[i] = Wire.read(); }
    float temp_mcp9808 = fram.uInt32 / 10000;

    // get MS5803 temp from the last 4 bytes, reversing order/endianness
    for (int8_t i = 4; i; i--) { fram.Byte[i] = Wire.read(); }
    float temp_ms5803 = fram.uInt32 / 10000;

    // print the results
    Serial.print("MS5803 Pressure: ");
    Serial.print(pressure);
    Serial.println(" mbar");

    Serial.print("MCP9808 Temperature: ");
    Serial.print(temp_mcp9808);
    Serial.println(" °C");

    Serial.print("MS5803 Temperature: ");
    Serial.print(temp_ms5803);
    Serial.println(" °C");

    // wait 5s and then repeat
    Serial.println("---");
    delay(5000);
}

#include <Arduino.h>

#include <Wire.h>

#define DEVICE_I2C_ADDRESS \

0x4D // I *think* this is the address it's using for itself

// https://github.com/NorthernWidget-Skunkworks/Project-Walrus/blob/b5d9cc1fdfe2cf16fb5048a1f9ff0b27253c3a94/Firmware/Walrus_I2C_5BA/Walrus_I2C_5BA.ino#L155

// A helpful union for flipping between bytes to longs

typedef union leFrame {

byte Byte[4]; // 4 bytes will occupy 4 bytes

uint32_t uInt32; // a single float occupies 4 bytes

} leFrame;

void setup() {

Wire.begin(); // join i2c bus (address optional for master)

Serial.begin(9600); // start serial for output

// NOTE: Something may have to happen here to "start the thing up"

// I can't tell if they intend that or not

}

void loop() {

// It looks like the control register (0x00) is being set to 0x7F

// (0b1111111) when values are being written (ie, values aren't ready) and

// to 0x80 (0b10000000) when it's ready.

// https://github.com/NorthernWidget-Skunkworks/Project-Walrus/blob/b5d9cc1fdfe2cf16fb5048a1f9ff0b27253c3a94/Firmware/Walrus_I2C_5BA/Walrus_I2C_5BA.ino#L242

byte control_flag = 0x7f;

while (control_flag == 0x7f) {

Wire.beginTransmission(

DEVICE_I2C_ADDRESS); // select device with "beginTransmission()"

Wire.write(0x00); // select starting register with "write()"

Wire.endTransmission(); // end write operation, as we just wanted to

// select the starting register

Wire.requestFrom(DEVICE_I2C_ADDRESS,

1); // select number of bytes to get from the device

// (1 byte in this case)

control_flag = Wire.read(); // read from the starting register

}

// We'll try reading all the registers at once sequentially instead of

// reading one after the other

// the registers are loaded starting on line 242:

// https://github.com/NorthernWidget-Skunkworks/Project-Walrus/blob/master/Firmware/Walrus_I2C_5BA/Walrus_I2C_5BA.ino#L242

Wire.beginTransmission(

DEVICE_I2C_ADDRESS); // select device with "beginTransmission()"

Wire.write(0x02); // select starting register with "write()"

// the first data register is pressure starting in register 0x02

Wire.endTransmission(); // end write operation, as we just wanted to select

// the starting register

// select number of bytes to get from the device

// + 4 for pressure in microbars (ie mbar*1000)

// + 4 for temp0 - This is the temperature from the MCP9808 (*10000.0)

// + 4 for temp1 - This is the temperature from the MS5803 (*10000.0)

Wire.requestFrom(DEVICE_I2C_ADDRESS, 12);

// We won't bother to read the next 8 bytes of unchanging sensor

// information:

// + 2 for model (uint16_t)

// + 2 for group id (uint16_t)

// + 2 for "INDID" ?dummy? (uint16_t)

// + 2 for firmware id (uint16_t))

// my helpful union

leFrame fram;

// NOTE: may need to flop endinaness for the values.

// if getting garbage, try switching all for loops to

// 'for (int8_t i = 0; i<4; i++)'

// get pressure from the first 4 bytes, reversing order/endianness

for (int8_t i = 4; i; i--) { fram.Byte[i] = Wire.read(); }

float pressure = fram.uInt32 / 1000;

// get MCP9808 temp from the next 4 bytes, reversing order/endianness

for (int8_t i = 4; i; i--) { fram.Byte[i] = Wire.read(); }

float temp_mcp9808 = fram.uInt32 / 10000;

// get MS5803 temp from the last 4 bytes, reversing order/endianness

for (int8_t i = 4; i; i--) { fram.Byte[i] = Wire.read(); }

float temp_ms5803 = fram.uInt32 / 10000;

// print the results

Serial.print("MS5803 Pressure: ");

Serial.print(pressure);

Serial.println(" mbar");

Serial.print("MCP9808 Temperature: ");

Serial.print(temp_mcp9808);

Serial.println(" °C");

Serial.print("MS5803 Temperature: ");

Serial.print(temp_ms5803);

Serial.println(" °C");

// wait 5s and then repeat

Serial.println("---");

delay(5000);

}