Understanding CodeCell Charging

The CodeCell offers flexibility in power supply options, allowing it to be powered through either the LiPo battery connector, a USB-C cable, or both simultaneously. This ensures adaptability across different use cases.

• LiPo Battery Connector: Designed for safe and easy battery connection without soldering.
• USB-C Port: Functions as a power source, charging port and a programming interface.

Power management is handled by the BQ24232 battery management chip, which supports Dynamic Power-Path Management (DPPM). This allows the CodeCell to run from external power while simultaneously charging the battery. The battery charging process follows three key phases:

1. Conditioning Precharge – Ensures safe charging of deeply discharged batteries.
2. Constant Current Charging – Provides a stable charge rate until the battery reaches a designated voltage threshold.
3. Constant Voltage Charging – Maintains a constant voltage while gradually reducing current to complete the charge cycle.

The BQ24232 chip regulates the output voltage, supporting a maximum output of 1500mA when powered by the LiPo battery and 450mA when powered via USB.

Default Charging Parameters

By default, the LiPo battery charge current is set to 90mA. This is optimized for the optional 170mAh LiPo battery, ensuring a safe and balanced charging rate.

Advanced users who wish to modify the charge current can do so by replacing 0402 resistor R12. However, this modification requires precise soldering skills, as 0402 components are extremely small. For further details, refer to the BQ24232 datasheet.

Charging Indicators

The CodeCell library provides visual feedback on charging and power status using the onboard RGB LED:

• Low Battery Warning: When battery voltage drops below 3.3V, the LED blinks red ten times, and the device enters Sleep Mode to conserve power.
• Charging Process: While charging via USB, the LED remains blue. When the battery reaches full charge, the LED transitions to a breathing-light animation.
• Battery Powered Mode: When running solely on battery power, the LED turns green and performs a breathing-light animation.

Keeping CodeCell Awake While Charging

By default, the CodeCell enters Sleep Mode while charging to maximize efficiency. However, starting from software release v1.2.7, users can override this behavior using the USBChargeState() function, which keeps the CodeCell awake during charging.

To keep the CodeCell awake while charging, add the following code to your setup function:

void setup() {
  Serial.begin(115200); // Set Serial baud rate to 115200
  // Ensure Tools/USB_CDC_On_Boot is enabled if using Serial

  myCodeCell.Init(LIGHT); // Initializes Light Sensor

  myCodeCell.USBChargeState(1); // Keeps CodeCell awake during charging
}

Behavior with USBChargeState(1):

• The battery will continue charging while CodeCell remains operational.
• The LED will blink blue, indicating that the device is powered via USB.

This feature is useful for applications that require CodeCell to remain active while charging, such as continuous data logging or IoT monitoring.

Conclusion:

With this information, you now have a full understanding of how CodeCell’s charging system works, including its default behaviors and customization options!

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