BSOM Evaluation Board - State of Charge

Hardware
1

I have been looking at adding a BSOM option for my counters for European and African customers. I plan to build my own carrier board but am starting with the BSOM Evaluation Board. I have not made any changes to the jumpers other than removing the four associated with Ethernet.

However, I cannot get an accurate state of charge or battery state using the System commands I typically use with the Boron. The documentation seems to imply that the BSOM will enable the bq24195 PMIC and MAX17043 fuel gauge by default. I can get battery voltage using the PMIC API call but what am I missing on using the System commands as I would like to maintain code compatibility with the Boron based devices.

I looked at this post for inspiration but my results are not the same when I run @tunahammer's code.

Here is my simplified sketch

#include "Particle.h"

SYSTEM_MODE(MANUAL);                        // This will enable user code to start executing automatically.
SYSTEM_THREAD(ENABLED);                             // Means my code will not be held up by Particle processes.

FuelGauge fuel;
SerialLogHandler LogHandler(LOG_LEVEL_INFO);

void setup() {
  fuel.begin();
  waitFor(Serial.isConnected, 10000);				// Wait for serial connection
  delay(1000);
  Log.info("Finished setup with state of charge %4.2f battery at %4.2fV", System.batteryCharge(), fuel.getVCell());
}

void loop() {
}

Output

0000002576 [app] INFO: Finished setup with state of charge -1.00 battery at 3.74V

Thanks,

Chip

2

Depending on how you set up the device, PMIC detection may or may not be enabled. I’d first try enabling it to see if that makes a difference.

SystemPowerConfiguration conf;
conf.feature(SystemPowerFeature::PMIC_DETECTION);
int res = System.setPowerConfiguration(conf);
3

@rickkas7 ,

Thank you for taking a look. Your approach makes sense since the BSOM can not always count on having a FuelGauge.

I updated the code to declare conf and then ran this in setup()

void setup() {
  fuel.begin();

  waitFor(Serial.isConnected, 10000);				// Wait for serial connection
  delay(1000);
  
  conf.feature(SystemPowerFeature::PMIC_DETECTION);
  int res = System.setPowerConfiguration(conf);
  Log.info("setPowerConfiguration=%d", res);

  Log.info("Finished setup with state of charge %4.2f batter at %4.2fV", System.batteryCharge(), fuel.getVCell());
}

But, this did not fix the issue:

0000002837 [app] INFO: setPowerConfiguration=0
0000002839 [app] INFO: Finished setup with state of charge -1.00 batter at 3.88V

This is a new evaluation board “M.2 SOM EVAL BOARD v1.1” and is is slightly different in appearance from the one in the docs:

The jumpers for the PM_INT, PM_SDA, PM_SCL are all closed.

Other things to try?

Thanks, Chip

4

The SoC and power source may not be available immediately after the PMIC is initialized. At least for testing, I’d try looping for a while and see if the result becomes available eventually. Maybe try every 5 seconds for a minute just to see if it’s a time-related issue or something else. You can do this in loop().

5

@rickkas7 ,

Thank you! Waiting a little bit was the solution. I wrote this sketch to see just how long - it very consistently comes back with the same answer 1.02 seconds.

This code works:


#include "Particle.h"

SYSTEM_MODE(MANUAL);                        // This will enable user code to start executing automatically.
SYSTEM_THREAD(ENABLED);                             // Means my code will not be held up by Particle processes.

FuelGauge fuel;
SystemPowerConfiguration conf;
SerialLogHandler LogHandler(LOG_LEVEL_INFO);

unsigned long clockStart = 0;

void setup() {
  waitFor(Serial.isConnected, 10000);				// Wait for serial connection
  delay(1000);

  fuel.begin();
  clockStart = millis();

  conf.feature(SystemPowerFeature::PMIC_DETECTION);
  int res = System.setPowerConfiguration(conf);
  Log.info("setPowerConfiguration %s", (res == 0) ? "was successful":"has failed");
}

void loop() {
    float stateOfCharge = System.batteryCharge();

    if (stateOfCharge == -1) delay(100);
    else {
      Log.info("State of charge %4.2f%% battery at %4.2fV after %4.2fseconds", System.batteryCharge(), fuel.getVCell(), (millis()-clockStart)/1000.0);
      while(1);
    }
}

Output

0000002536 [app] INFO: setPowerConfiguration was successful
0000003543 [app] INFO: State of charge 90.39% battery at 4.09V after 1.02seconds

Thank you for your help on this.

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6

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