Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

RE: Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

BennyC — Sun, 13 Jun 2021 10:00:48 GMT

Sounds good. I will go through those and open up a new case for any further questions.

Thanks again for your help!

Benny

RE: Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

Simon — Thu, 10 Jun 2021 09:59:32 GMT

[quote user="BennyC"]Could I suggest a similar sample as a starting point for C++? Even a sample working program (with ADC, I2C) if not a full tutorial.[/quote]

Maybe the sample https://github.com/nrfconnect/sdk-zephyr/blob/e4f87fba1b8785dcdcd1a3872e592bd7f7b53039/samples/subsys/cpp/cpp_synchronization/src/main.cpp would be a good option.

[quote user="BennyC"]I went through the Edge Impulse and Pelion examples, it looks like both of of those use C++ programs running on the embedded platform that can be called by C programs also running on the embedded platform. Basically I would need to write my own C++ wrapper to the biometrics C++ libraries and run it as a thread that can be called by my C programs, is that correct?[/quote]

I don't know enough about this to give you a qualified answer at the moment. However, check out the application above, that uses a cpp main file.

This may be worth taking a look at as well https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.1/zephyr/reference/kernel/other/cxx_support.html

Could you open a new DevZone case about this. Since it's not related to the initial question. You could also try to ask the Zephyr community on slack, or any of these places: https://docs.zephyrproject.org/2.3.0/guides/getting-help.html#asking-for-help

Best regards,

Simon

RE: Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

BennyC — Wed, 09 Jun 2021 00:30:54 GMT

Thank-you Simon, you answered the original question, so we can mark this thread as answered. Regarding the bigger question of C++ support for sensor algorithms, I will follow up separately, but just wanted a bit of clarification on what you had mentioned here.

I went through the Edge Impulse and Pelion examples, it looks like both of of those use C++ programs running on the embedded platform that can be called by C programs also running on the embedded platform. Basically I would need to write my own C++ wrapper to the biometrics C++ libraries and run it as a thread that can be called by my C programs, is that correct?

The option of manually porting the C++ biometrics libraries to C might not be sustainable for me given the large amount, and continually growing and updating revised C++ biometrics libraries in this (health sensors) field.

The other option of using the command line, west, VS Code, Ozone looks promising and possibly the most sustainable. I looked into this and am comfortable with those tools, but the biggest hurdle appears to be having the base C++ code to get started with the board (nRF5340dk in this case). Is there a sample like a Blinky in C++ for a board like the nRF5340dk? I am aware you wrote a tutorial for Blinky in C. Could I suggest a similar sample as a starting point for C++? Even a sample working program (with ADC, I2C) if not a full tutorial.

Thanks-very much

RE: Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

Simon — Tue, 11 May 2021 14:37:50 GMT

It seems like the support for C++ in NCS is better now. I talked to a developer internally. He said the the edge_impulse sample works fine. He also mentioned the pelion_client application, which also uses C++ (see pelion_client/src/modules). However, it seems like there are some issues with SES:

"It is not possible to build Thread samples using SEGGER Embedded Studio (SES). SES does not support .cpp files in nRF Connect SDK projects. (NCSDK-5014)"

If you want to use SES, it seems like you need to convert the library to C-code. If not you can build using command line and west+VS code and debug using Ozone.

RE: Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

Simon — Tue, 11 May 2021 13:42:02 GMT

[quote user="BennyC"]

I have to ask, when I build and debug now it always stops at this line 12 of my main.c

const struct device *dev = device_get_binding(DT_LABEL(DT_INST(0, max_max30101)));

[/quote]

It seems like this is something that SEGGER does automatically at start up, it will find main and stop there. Similar to what Ozone does, as discussed here.

The reason it stops at device_get_binding() instead of the start of main(), is because the code is optimized by default. I confirmed this by turning of optimizations (set CONFIG_DEBUG_OPTIMIZATIONS=y in prj.conf) and saw that it stopped at main().

[quote user="BennyC"]

Now that I can get sensor readings I know I need to perform algorithms to get the biometrics (Heart Rate, Blood Oxygen Saturation). In all of my searching, those algorithms only exist for the Arduino.

ie: https://github.com/sparkfun/SparkFun_MAX3010x_Sensor_Library

If I am trying to get those readings for the nRF5340, what are the best options?

Manually port the Arduino C++ code to Zephyr C code for the nRF5340 myself?

[/quote]

This DevZone ticket may be helpful regarding this question: https://devzone.nordicsemi.com/f/nordic-q-a/57362/how-to-add-c-file-to-nrf9160-project-in-ses. It seems like C++ is not fully supported in SES. We do have more samples using C++ now, like the edge_impulse sample, which uses the library ei_wrapper.cpp and in addition we support thread in NCS, which uses C++, so it seems like the situation has changed. I will ask internally to get more information about this.

RE: Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

BennyC — Mon, 10 May 2021 07:59:58 GMT

Thanks very much Simon. I made the changes, got past the "Inactive Sensor Channel" errors and am now getting sensor readings! I always appreciate seeing your posts here.

I have to ask, when I build and debug now it always stops at this line 12 of my main.c

const struct device *dev = device_get_binding(DT_LABEL(DT_INST(0, max_max30101)));

#include <zephyr.h>
#include <sys/printk.h>
#include <drivers/sensor.h>
#include <stdio.h>

void main(void)
{
	struct sensor_value green;
	struct sensor_value ir;
	struct sensor_value red;

	const struct device *dev = device_get_binding(DT_LABEL(DT_INST(0, max_max30101)));

	if (dev == NULL) {
		printf("Could not get max30101 device\n");
		return;
	}

	while (1) {
		sensor_sample_fetch(dev);
		printf("\n==============================================================================\n");
		
		sensor_channel_get(dev, SENSOR_CHAN_GREEN, &green);
		printf("GREEN=%d\n", green.val1);

		sensor_channel_get(dev, SENSOR_CHAN_IR, &ir);
		printf("IR=%d\n", ir.val1);
		
		sensor_channel_get(dev, SENSOR_CHAN_RED, &red);
		printf("RED=%d\n", red.val1);

		printf("\n");
		k_sleep(K_MSEC(5000));
	}
}

I can click on the "Continue Execution" green play button and it continues and the rest works as expected, but just wondering if there is a fix for it always stopping there.

ie: https://github.com/sparkfun/SparkFun_MAX3010x_Sensor_Library

If I am trying to get those readings for the nRF5340, what are the best options?

Manually port the Arduino C++ code to Zephyr C code for the nRF5340 myself?

Do you know of any initiatives that would be working on this kind of porting already? (I think it would be a fairly high demand common algorithm to work with wearables.)

RE: Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

Simon — Wed, 05 May 2021 10:18:17 GMT

I took a look at the max30101 code and I think I know how to go about this.

If you take a look at this code snippet: https://github.com/nrfconnect/sdk-zephyr/blob/v2.4.99-ncs2/drivers/sensor/max30101/max30101.c#L232-L237, you will see how the fifo channels are associated with the led channels.

I think you can think of it like this, if I have understood it correctly:

.mode = MAX30101_MODE_MULTI_LED,
.slot[<fifo_chan>] = <led_chan>+1,
.slot[<fifo_chan>] = <led_chan>+1,
.slot[<fifo_chan>] = <led_chan>+1,
.slot[<fifo_chan>] = <led_chan>+1,

Most of the configs CONFIG_MAX30101_SLOTx will default to 0, which means they are disabled, and that's the reason it fails for you I think.

So in your prj.conf, in addition to enabling CONFIG_MAX30101_MULTI_LED_MODE, try assigning a value to the configs CONFIG_MAX30101_SLOTx: https://github.com/nrfconnect/sdk-zephyr/blob/v2.4.99-ncs2/drivers/sensor/max30101/Kconfig#L141-L199

I don't have a max30101 sensor at hand, and haven't tested this, so I may have overlooked something.

Best regards,

Simon

RE: Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

BennyC — Mon, 03 May 2021 00:33:23 GMT

Thank-you very much for the reply, Wasan.

I edited my prj.conf according to your suggestions, re-opened the project, re-built, and re-run, but I am getting the same output as before where RED is always 0 and IR is always 29473.

Here is my prj.conf:

CONFIG_SERIAL=y
CONFIG_STDOUT_CONSOLE=y
CONFIG_LOG=y
CONFIG_I2C=y
CONFIG_SENSOR=y
CONFIG_SENSOR_LOG_LEVEL_DBG=y
CONFIG_MAX30101=y
CONFIG_MAX30101_MULTI_LED_MODE=y
CONFIG_MAX30101_LED2_PA=0x0f

In max30101.c the part that confuses me is line 78 to 87 since fifo_chan always gets set to 3 when led_chan is 1 or 0, which is what throws the "Inactive sensor channel" error. What is the right way to activate those 2 channels correctly in code and as a result set fifo_chan to a correct value and avoid the error?

Lines 195 to 211 Initialize the channel map and active channel count, but should I change the code there (and to what?) or is that only for initialization as the comments state?

/*
 * Copyright (c) 2017, NXP
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT max_max30101

#include <logging/log.h>

#include "max30101.h"

LOG_MODULE_REGISTER(MAX30101, CONFIG_SENSOR_LOG_LEVEL);

static int max30101_sample_fetch(const struct device *dev,
				 enum sensor_channel chan)
{
	struct max30101_data *data = dev->data;
	const struct max30101_config *config = dev->config;
	uint8_t buffer[MAX30101_MAX_BYTES_PER_SAMPLE];
	uint32_t fifo_data;
	int fifo_chan;
	int num_bytes;
	int i;

	/* Read all the active channels for one sample */
	num_bytes = data->num_channels * MAX30101_BYTES_PER_CHANNEL;
	if (i2c_burst_read(data->i2c, config->i2c_addr,
			   MAX30101_REG_FIFO_DATA, buffer, num_bytes)) {
		LOG_ERR("Could not fetch sample");
		return -EIO;
	}

	fifo_chan = 0;
	for (i = 0; i < num_bytes; i += 3) {
		/* Each channel is 18-bits */
		fifo_data = (buffer[i] << 16) | (buffer[i + 1] << 8) |
			    (buffer[i + 2]);
		fifo_data &= MAX30101_FIFO_DATA_MASK;

		/* Save the raw data */
		data->raw[fifo_chan++] = fifo_data;
	}

	return 0;
}

static int max30101_channel_get(const struct device *dev,
				enum sensor_channel chan,
				struct sensor_value *val)
{
	struct max30101_data *data = dev->data;
	enum max30101_led_channel led_chan;
	int fifo_chan;

	switch (chan) {
	case SENSOR_CHAN_RED:
		led_chan = MAX30101_LED_CHANNEL_RED;
		break;

	case SENSOR_CHAN_IR:
		led_chan = MAX30101_LED_CHANNEL_IR;
		break;

	case SENSOR_CHAN_GREEN:
		led_chan = MAX30101_LED_CHANNEL_GREEN;
		break;

	default:
		LOG_ERR("Unsupported sensor channel");
		return -ENOTSUP;
	}

	/* Check if the led channel is active by looking up the associated fifo
	 * channel. If the fifo channel isn't valid, then the led channel
	 * isn't active.
	 */
	fifo_chan = data->map[led_chan];

// begin what I added
	LOG_ERR("led_chan: %d. fifo_chan: %d. MAX30101_MAX_NUM_CHANNELS: %d  ", led_chan, fifo_chan, MAX30101_MAX_NUM_CHANNELS);
// end what I added

	if (fifo_chan >= MAX30101_MAX_NUM_CHANNELS) {
		LOG_ERR("Inactive sensor channel\n");
		return -ENOTSUP;
	}


	/* TODO: Scale the raw data to standard units */
	val->val1 = data->raw[fifo_chan];
	val->val2 = 0;

	return 0;
}

static const struct sensor_driver_api max30101_driver_api = {
	.sample_fetch = max30101_sample_fetch,
	.channel_get = max30101_channel_get,
};

static int max30101_init(const struct device *dev)
{
	const struct max30101_config *config = dev->config;
	struct max30101_data *data = dev->data;
	uint8_t part_id;
	uint8_t mode_cfg;
	uint32_t led_chan;
	int fifo_chan;

	/* Get the I2C device */
	data->i2c = device_get_binding(config->i2c_label);
	if (!data->i2c) {
		LOG_ERR("Could not find I2C device");
		return -EINVAL;
	}

	/* Check the part id to make sure this is MAX30101 */
	if (i2c_reg_read_byte(data->i2c, config->i2c_addr,
			      MAX30101_REG_PART_ID, &part_id)) {
		LOG_ERR("Could not get Part ID");
		return -EIO;
	}
	if (part_id != MAX30101_PART_ID) {
		LOG_ERR("Got Part ID 0x%02x, expected 0x%02x",
			    part_id, MAX30101_PART_ID);
		return -EIO;
	}

	/* Reset the sensor */
	if (i2c_reg_write_byte(data->i2c, config->i2c_addr,
			       MAX30101_REG_MODE_CFG,
			       MAX30101_MODE_CFG_RESET_MASK)) {
		return -EIO;
	}

	/* Wait for reset to be cleared */
	do {
		if (i2c_reg_read_byte(data->i2c, config->i2c_addr,
				      MAX30101_REG_MODE_CFG, &mode_cfg)) {
			LOG_ERR("Could read mode cfg after reset");
			return -EIO;
		}
	} while (mode_cfg & MAX30101_MODE_CFG_RESET_MASK);

	/* Write the FIFO configuration register */
	if (i2c_reg_write_byte(data->i2c, config->i2c_addr,
			       MAX30101_REG_FIFO_CFG, config->fifo)) {
		return -EIO;
	}

	/* Write the mode configuration register */
	if (i2c_reg_write_byte(data->i2c, config->i2c_addr,
			       MAX30101_REG_MODE_CFG, config->mode)) {
		return -EIO;
	}

	/* Write the SpO2 configuration register */
	if (i2c_reg_write_byte(data->i2c, config->i2c_addr,
			       MAX30101_REG_SPO2_CFG, config->spo2)) {
		return -EIO;
	}

	/* Write the LED pulse amplitude registers */
	if (i2c_reg_write_byte(data->i2c, config->i2c_addr,
			       MAX30101_REG_LED1_PA, config->led_pa[0])) {
		return -EIO;
	}
	if (i2c_reg_write_byte(data->i2c, config->i2c_addr,
			       MAX30101_REG_LED2_PA, config->led_pa[1])) {
		return -EIO;
	}
	if (i2c_reg_write_byte(data->i2c, config->i2c_addr,
			       MAX30101_REG_LED3_PA, config->led_pa[2])) {
		return -EIO;
	}

#ifdef CONFIG_MAX30101_MULTI_LED_MODE
	uint8_t multi_led[2];

	/* Write the multi-LED mode control registers */
	multi_led[0] = (config->slot[1] << 4) | (config->slot[0]);
	multi_led[1] = (config->slot[3] << 4) | (config->slot[2]);

	if (i2c_reg_write_byte(data->i2c, config->i2c_addr,
			       MAX30101_REG_MULTI_LED, multi_led[0])) {
		return -EIO;
	}
	if (i2c_reg_write_byte(data->i2c, config->i2c_addr,
			       MAX30101_REG_MULTI_LED + 1, multi_led[1])) {
		return -EIO;
	}
#endif

	/* Initialize the channel map and active channel count */
	data->num_channels = 0U;
	for (led_chan = 0U; led_chan < MAX30101_MAX_NUM_CHANNELS; led_chan++) {
		data->map[led_chan] = MAX30101_MAX_NUM_CHANNELS;
	}

	/* Count the number of active channels and build a map that translates
	 * the LED channel number (red/ir/green) to the fifo channel number.
	 */
	for (fifo_chan = 0; fifo_chan < MAX30101_MAX_NUM_CHANNELS;
	     fifo_chan++) {
		led_chan = (config->slot[fifo_chan] & MAX30101_SLOT_LED_MASK)-1;
		if (led_chan < MAX30101_MAX_NUM_CHANNELS) {
			data->map[led_chan] = fifo_chan;
			data->num_channels++;
		}
	}

	return 0;
}

static struct max30101_config max30101_config = {
	.i2c_label = DT_INST_BUS_LABEL(0),
	.i2c_addr = DT_INST_REG_ADDR(0),
	.fifo = (CONFIG_MAX30101_SMP_AVE << MAX30101_FIFO_CFG_SMP_AVE_SHIFT) |
#ifdef CONFIG_MAX30101_FIFO_ROLLOVER_EN
		MAX30101_FIFO_CFG_ROLLOVER_EN_MASK |
#endif
		(CONFIG_MAX30101_FIFO_A_FULL <<
		 MAX30101_FIFO_CFG_FIFO_FULL_SHIFT),

#if defined(CONFIG_MAX30101_HEART_RATE_MODE)
	.mode = MAX30101_MODE_HEART_RATE,
	.slot[0] = MAX30101_SLOT_RED_LED1_PA,
	.slot[1] = MAX30101_SLOT_DISABLED,
	.slot[2] = MAX30101_SLOT_DISABLED,
	.slot[3] = MAX30101_SLOT_DISABLED,
#elif defined(CONFIG_MAX30101_SPO2_MODE)
	.mode = MAX30101_MODE_SPO2,
	.slot[0] = MAX30101_SLOT_RED_LED1_PA,
	.slot[1] = MAX30101_SLOT_IR_LED2_PA,
	.slot[2] = MAX30101_SLOT_DISABLED,
	.slot[3] = MAX30101_SLOT_DISABLED,
#else
	.mode = MAX30101_MODE_MULTI_LED,
	.slot[0] = CONFIG_MAX30101_SLOT1,
	.slot[1] = CONFIG_MAX30101_SLOT2,
	.slot[2] = CONFIG_MAX30101_SLOT3,
	.slot[3] = CONFIG_MAX30101_SLOT4,
#endif

	.spo2 = (CONFIG_MAX30101_ADC_RGE << MAX30101_SPO2_ADC_RGE_SHIFT) |
		(CONFIG_MAX30101_SR << MAX30101_SPO2_SR_SHIFT) |
		(MAX30101_PW_18BITS << MAX30101_SPO2_PW_SHIFT),

	.led_pa[0] = CONFIG_MAX30101_LED1_PA,
	.led_pa[1] = CONFIG_MAX30101_LED2_PA,
	.led_pa[2] = CONFIG_MAX30101_LED3_PA,
};

static struct max30101_data max30101_data;

DEVICE_DT_INST_DEFINE(0, max30101_init, device_pm_control_nop,
		    &max30101_data, &max30101_config,
		    POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY,
		    &max30101_driver_api);

RE: Getting "inactive sensor channel" when using more than one channel on heart rate sensor MAX30101 sample code

wasan — Sun, 02 May 2021 03:17:35 GMT

For fix RED LED is 0. I think you can try add config as below to prj.conf

CONFIG_MAX30101_MULTI_LED_MODE=y

About IR LED is always at the maximum value. I think you can try setup led power to reduce the brightness.

CONFIG_MAX30101_LED2_PA=0x0f

You can see all max30101 configulation at "$YOUR_SDK_DIR\ncs\v1.5.0\zephyr\drivers\sensor\max30101\Kconfig"

This is a example for config IR LED power from Kconfig file.

config MAX30101_LED2_PA
hex "LED2 (IR) pulse amplitude"
range 0 0xff
default 0x33
help
Set the pulse amplitude to control the LED2 (IR) current. The actual
measured LED current for each part can vary significantly due to the
trimming methodology.
0x00 = 0.0 mA
0x01 = 0.2 mA
0x02 = 0.4 mA
0x0f = 3.1 mA
0xff = 50.0 mA

Wasan