Get stuck in mcp.analogRead loop about arduino_mcp3x6x_library HOT 7 CLOSED

Hey Felix,

I've run into this exact issue (also with the ESP32S3). I'm currently working on a PR to make this library fully compatible ( GH-5), but for the time being here's the fix in order to get analogRead to work.

In MCP3x6x.h

typedef union {
     struct {
       struct __attribute__((__packed__)) {
         bool por;     //!< status: power on reset
         bool crccfg;  //!< status: crc
         bool dr;      //!< status: data ready
       };
       uint8_t      : 1;  //!< !addr[0]
       uint8_t addr : 2;  //!< addresse
      uint8_t      : 2;  //!< EMTPY
    };
    uint8_t raw;
  } status_t;
  status_t _status;

Must get updated to

typedef union {
     struct {
       struct __attribute__((__packed__)) {
         bool por   : 1;  //!< status: power on reset
         bool crccfg : 1;  //!< status: crc
         bool dr    : 1;  //!< status: data ready
       };
       uint8_t      : 1;  //!< !addr[0]
       uint8_t addr : 2;  //!< addresse
      uint8_t      : 2;  //!< EMTPY
    };
    uint8_t raw;
  } status_t;
  status_t _status;

There's an issue on the ESP32S3 specifically where the bit assignment in the union doesn't work properly unless explicitly stated.

You can also optionally add _status = read(&adcdata); after the

while (!_status.dr) {
       _status = read(&adcdata);
}

in analogRead; however, I'm not sure if this is necessary or not.

Best,

from arduino_mcp3x6x_library.

could you please specify what you mean by:
Also dude to the layout error in swap the pin definition of MISO & MOSI in the class Constructor .
where did I swap something?

from arduino_mcp3x6x_library.

nerdyscout

could you please specify what you mean by: Also dude to the layout error in swap the pin definition of MISO & MOSI in the class Constructor . where did I swap something?

This is the problem on my end. It is dude to the wrong PCB layout of my project.
thank you for your reply

from arduino_mcp3x6x_library.

Mirageofmage
Thank you for your quick reply , I've tried what you suggest and it works now!
But the readings keeps on increasing even when I do nothing to the device.

By the way, I should have mentioned this in my post that I'm using MCP3562R: dual channel variant.

This is my circuit:

I'm trying to read ADC readings from Device 1. So I'm assuming I should change MCP_CH0 definition in MCP3x6x.h from 0x08 to 0x01

from arduino_mcp3x6x_library.

I manage to make it work now.

What I did was twick the configuration a bit setDataFormat(data_format::SGN_DATA);
And change the reference voltage to 3.3. Also as I mentioned in my last post I change MCP_CH0 definition in MCP3x6x.h from 0x08 to 0x01.
And now I'm getting the readings almost 6.6 which is what it should be while off load.

Apart from the topic, shouldn't the code here

from arduino_mcp3x6x_library.

There is no begin() in SPIClass which takes any parameters, therefore no :)

Please check the examples, there I use a setup with a custom SPI, this should also help with your pin swap without modifiying my lib.

SPIClass mySPI(&sercom1, 12, 13, 11, SPI_PAD_0_SCK_1, SERCOM_RX_PAD_3);
MCP3561 mcp(8, 7, 10, &mySPI, 11, 12, 13);
...
  _spi        = theSPI;
...
 _spi->begin(); 

As you can see the custom SPI mySPI is passed through the constructor into the privat member _spi which therefore got the correct pin definitions.

As far as I understand your schematic your try to do some differential reading as well as a single ended reading. There should be nothing wrong with this, but my personal approach would be to handle both the same way... anyway, you should not need to change the definition of MCP_CH0 but instead mcp.enableScanChannel(MCP_DIFFA); for enabling reading differntial signals and mcp.enableScanChannel(MCP_CH2) for reading pressure - altleast in ScanMode.
In MuxMode just do int32_t adcdata = mcp.analogRead(MCP_DIFFA); or MCP_CH2 whenever you like.

from arduino_mcp3x6x_library.

There is no begin() in SPIClass which takes any parameters, therefore no :)

Well , it seem that Arduino core didn't provide it but in ESP32 core it does. Check out the following link for SPI library in esp32 core
(http://github.com/espressif/arduino-esp32/blob/9275dbff942bb2ccce62632607500ad27dd0513a/libraries/SPI/src/SPI.h#L63)
And yes I did try out your code as well. But again it seems to be Arduino and ESP32 core difference I can't get your configurations to work.

int32_t adcdata = mcp.analogRead(MCP_DIFFA);

Ah, you did provide the settings I want. This is great it feels weird to modifiy your library.
Thanks for this amazing library!

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