MLX90640 and M5Fire/M5Stack

sheepDog

Hello,

I received my MLX90640 thermo cam and used this program to test it:
https://github.com/dtomyy/M5Stack-MLX90640-Thermal-Camera/blob/master/M5Stack-MLX90640-Thermal-Camera.ino

I switched the debug level to verbose to see all errors and warnings.
I got some problems with the SD-card. This was ok because there is no SD-card inside M5Stack.

09:42:54.222 -> [W][sd_diskio.cpp:137] sdCommand(): no token received
09:42:54.325 -> [W][sd_diskio.cpp:137] sdCommand(): no token received
09:42:54.431 -> [W][sd_diskio.cpp:471] ff_sd_initialize(): GO_IDLE_STATE failed
09:42:54.431 -> [E][sd_diskio.cpp:739] sdcard_mount(): f_mount failed 0x(3)
09:42:54.431 -> OK
09:42:54.431 -> M5.begin ok
09:42:54.431 -> Wire begin ok
09:42:54.814 -> M5Stack MLX90640 IR Camera
09:42:55.541 -> Parameter extraction failed
09:42:55.541 -> Error: Sensor did not ack
09:42:55.604 -> No ack read
09:42:55.605 -> No ack read
09:42:55.605 -> No ack read

The main problem started at this errorline "Parameter extraction failed". The program found the MLX90640 but it didn't read the data from the sensor correct. To comment the ack-check in MLX90640_I2CRead didn't work for me. I read this at https://forums.pimoroni.com/t/mlx90640-no-ack/8662/12
Can anyone help me?

heybin

hello
you need update arduino-esp32 to the newest
see https://github.com/espressif/arduino-esp32 ,and test it
the sd card mount in M5.begin()
if you want init sd card, you can use M5.begin(true, false, true) instead M5.begin(), it will be ok

sheepDog

Hello,
I continued testing and I found two problems:

It is necessary to take new arduino library. @heybin: Thanks.
Problem with "MLX90640_I2CRead". I changed this in the function:

   /*
    if (Wire.endTransmission(false) != 0) //Do not release bus
    {
      Serial.println("No ack read");
      return (0); //Sensor did not ACK
    }*/
    Wire.endTransmission(false);

Now it worked for me.

heybin

Hello,
In the new arduino-esp32 library ,need to pay attention to in new IIC communication：

Wire.endTransmission(false) run ok will return 7, not 0

sheepDog

Hello heybin,
thank you for the information of the new return value from "Wire.end".

Do you know why the second part in "MLX90640_I2CWrite" worked?

int MLX90640_I2CWrite(uint8_t _deviceAddress, unsigned int writeAddress, uint16_t data)
{
  Wire.beginTransmission((uint8_t)_deviceAddress);
  Wire.write(writeAddress >> 8); //MSB
  Wire.write(writeAddress & 0xFF); //LSB
  Wire.write(data >> 8); //MSB
  Wire.write(data & 0xFF); //LSB
  if (Wire.endTransmission() != 0)
  {
    //Sensor did not ACK
    Serial.println("Error: Sensor did not ack");
    return (-1);
  }

I changed "MLX90640_I2CRead" to:

int MLX90640_I2CRead(uint8_t _deviceAddress, unsigned int startAddress, unsigned int nWordsRead, uint16_t *data)
{
  //Caller passes number of 'unsigned ints to read', increase this to 'bytes to read'
  uint16_t bytesRemaining = nWordsRead * 2;
  //It doesn't look like sequential read works. Do we need to re-issue the address command each time?
  uint16_t dataSpot = 0; //Start at beginning of array
  //Setup a series of chunked I2C_BUFFER_LENGTH byte reads
  while (bytesRemaining > 0)
  {
    Wire.beginTransmission(_deviceAddress);
    Wire.write(startAddress >> 8); //MSB
    Wire.write(startAddress & 0xFF); //LSB
    if (Wire.endTransmission(false) != 7) //Do not release bus
    {
      Serial.println("No ack read");
      return (0); //Sensor did not ACK
    }
    uint16_t numberOfBytesToRead = bytesRemaining;
...

heybin

hello,
the return mean:

typedef enum {
    I2C_ERROR_OK=0,
    I2C_ERROR_DEV,
    I2C_ERROR_ACK,
    I2C_ERROR_TIMEOUT,
    I2C_ERROR_BUS,
    I2C_ERROR_BUSY,
    I2C_ERROR_MEMORY,
    I2C_ERROR_CONTINUE,
    I2C_ERROR_NO_BEGIN
} i2c_err_t;

when Wire.endTransmission() mean Wire.endTransmission(true), so success return I2C_ERROR_OK
Wire.endTransmission(false) success return I2C_ERROR_CONTINUE

sheepDog

Hello,

thank you for the good explanation.