How can I set the trigger of the adxl362 to a specific value?

[Bergmann]

Hi, I am working with the adxl362 sensor on the Thingy91 and I want to set the trigger of the sensor to a specific value. 

In the datasheet (https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL362.pdf), it says that the threshold should be adjustable. In the Zephyr Documentation (https://docs.zephyrproject.org/latest/reference/peripherals/sensor.html), I found that there is a SENSOR_TRIG_THRESHOLD and that it can be configurated with  SENSOR_ATTR_LOWER_THRESH and SENSOR_ATTR_UPPER_THRESH, but I have no idea how to use them in the code. Does someone could give me an example code line on how to set the trigger?

Thanks for your help!

[Øyvind]

Hello, 
 

Does someone could give me an example code line on how to set the trigger?

Have a look at our BH1749 sample (nrf\samples\sensor\bh1749), and the ADXL362 drivers found here: zephyr\drivers\sensor\adxl362\

Kind regards,
Øyvind

[Bergmann]

Hi, sorry for the delay.

That doesn't really work, my skills are not good enough.

Do you maybe have a example code, where you write the register of the adxl362 or another sensor? 

I tried to import the driver files in zephyr\drivers\sensor\adxl362\, but when I wanted to write a register, I got an spi error. So could you maybe provide an example program? 

 

Thanks for your help!

[MJD093]

Hi there,

I had a similar issue in the past with the ADXL362. Have a look at this thread and try running the example code I listed there. You should be able to read the ADXL362's part ID. From that you should be able to start reading through the Datasheet and building you application. devzone.nordicsemi.com/.../how-to-get-accelerometer-value-of-thingy-91

[Bergmann]

Hi, thanks for your code example. I am now able to read the registers too. 

How did you managed to write the registers? 

void spi_test_send(void)
{
	int err;
	static u8_t tx_buffer[1] = {0x0F};
	static u8_t rx_buffer[2]= {0x0A, 0x20};

        gpio_pin_write(cs_gpio, cd_pin, 0);


	const struct spi_buf tx_buf = {
		.buf = tx_buffer,
		.len = sizeof(tx_buffer)
	};
	const struct spi_buf_set tx = {
		.buffers = &tx_buf,
		.count = 1
	};

	struct spi_buf rx_buf = {
		.buf = rx_buffer,
		.len = sizeof(rx_buffer),
	};
	const struct spi_buf_set rx = {
		.buffers = &rx_buf,
		.count = 1
	};

	err = spi_transceive(spi_dev, &spi_cfg, &tx, &rx);
	if (err) {
		printk("SPI error: %d\n", err);
	} else {
		/* Connect MISO to MOSI for loopback */
		printk("TX sent: %x\n", tx_buffer[0]);
		printk("RX recv: %x\n", rx_buffer[0]);
	}
        gpio_pin_write(cs_gpio, cd_pin, 1);
}

I wanted to try to write the 0x20 (Lower Threshold) with the value 0x0F with the code above.

Do I have to add the 0x0A? Or how do I have to write these two lines correctly then?:

static u8_t tx_buffer[1] = {0x0F};
static u8_t rx_buffer[2]= {0x0A, 0x20};

Do I need here the 

gpio_pin_write(cs_gpio, cd_pin, 0);
gpio_pin_write(cs_gpio, cd_pin, 1);

like in the read function?

Thanks for your help and your answers!

[Bergmann]

I solved it by my own with the help of the timing diagram:

I have a working code for the read area of the diagram and I need a code that works for the write area of the diagram. I need to expand the buffer and send 3 bytes instead of 2. The working code is:

void spi_write_reg(void)
{
  u8_t cmd =      0x0A;
  u8_t reg_addr = 0x20; // register, that you want to write
  u8_t value = 0x46; // value, that you want to set
  void *data = &value;
  int length = 1;
	u8_t access[3] = { cmd, reg_addr, value };

  gpio_pin_write(cs_gpio, cd_pin, 0);

	const struct spi_buf buf[2] = {
		{
			.buf = access,
			.len = 3
		},
		{
			.buf = data,
			.len = length
		}
	};
	struct spi_buf_set tx = {
		.buffers = buf,
	};


	const struct spi_buf_set rx = {
		.buffers = buf,
		.count = 2
	};

	tx.count = 1;

	int spi_result = spi_transceive(spi_dev, &spi_cfg, &tx, &rx);

 // printk("SPI result: %d\n",spi_result);
  printk("Value: 0x%02X\n", value);

  gpio_pin_write(cs_gpio, cd_pin, 1);

}