bobveringa / hscdtd008a-library Goto Github PK

Add support for the Offset Drift feature of the HSCDTD008A sensor.

This allows the user to apply a static offset to all the values.

Summary:
The order of temperature compensation and offset calibration seems to be order dependent in the latest build.

A HSCDTD_STAT_NO_DATA error is triggered if temperature compensation is done before offset calibration. Validation is needed if this is also the case for the C driver layer, or if this only happens in the Wrapper layer. I have no reason to believe the wrapper layer causes any of this behavior, but validating it seems a good first step.

Initial code analysis shows no obvious reason why the order of these operations should matter, so more investigation is needed.

Workaround
The workaround is to do offset calibration before temperature compensation.

Additional details:
A logic analyzer clearly shows the driver attempting to check the status register, but only 0x00 is returned from it.

If both temperature compensation and offset calibration are disabled, only 2 attempts are needed before data is available.

If only offset calibration is enabled, it takes ~26 attempts:

if only temperature compensation is enabled, it takes ~29 attempts:

If both are enabled in the "wrong" order, and the number of max-attempts is increased from 50 to 100, data is available within 32 attempts. This does not make any sense to me.

It could have something to do with these functions explicitly setting the device in the FORCE state.
Because the DRDY (white) pin is high about 93ms after starting a reading.

In any case, something goes wrong when using TCS or OCL (or a combination of the 2) as the number of attempts is just way to high.

Code snippet to test:

void setup() {
  hscdtd_status_t status;

  Serial.begin(9600);

  geomag.begin();
  // If you know the I2C address is different than in the provided
  // data sheet. Uncomment the line below, and configure the address.
  geomag.begin(0x0F);

  // Initialize the hardware.
  status = geomag.initialize();
  if (status != HSCDTD_STAT_OK) {
    Serial.println("Failed to initialize sensor. Check wiring.");

    // Halt program here.
    while (true) { delay(1); }
  }
  // Compensate for temperature.
  geomag.temperatureCompensation();

  geomag.offsetCalibration();
}

Add support for the Data Ready Pin Support to the Arduino Layer. Including some examples.

Currently, the driver supports the Force State for reading data from the sensor. The HSCDTD008A also supports configuring the sensor to a specific frequency and reading sensor data without explicitly starting a read operation.

The goal is to research how Normal State can be properly supported on an Arduino. In addition, some examples should be created that clearly show how it should be used.

• Investigate how Normal State works
• Implement C Driver (If required)
• Implement Wrapper layer
• Create example(s)

As @tilman1 pointed out in #9 the address for the chip is hard-coded in the platform file. Given that this are cheap chips, they are likely to have addresses that are all over the place.

This means a modification is needed to allow other platforms to set up all required components for I2C functionality.