Charger Design Specifications
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Below is a ready-to-flash Arduino-style sketch for your nRF52840 (e.g. Adafruit Feather nRF52840 Express or any board that exposes the raw nRF52840 pins).
• STAT from MCP73831T-2ACI/OT is open-drain, active LOW while charging.
• Green LED (front-panel indicator) is wired so that driving the MCU pin HIGH turns the LED ON.
• Green LED (front-panel indicator) is wired so that driving the MCU pin HIGH turns the LED ON.
Adjust the GPIO numbers (
#define) to match your PCB routing.Cpp
/* * Wireless-controller charging LED * Works with MCP73831 STAT pin (active-LOW while charging) * Target MCU: nRF52840, Arduino-core */ #include /* ---------- Pin definitions (edit to match your board) ---------- */ #define PIN_STAT 11 // nRF52840 P0.11 TASKS_HFCLKSTOP = 1; // stop external 64 MHz crystal } void loop() { bool charging = (digitalRead(PIN_STAT) == LOW); // LOW = charging digitalWrite(PIN_LED, charging ? HIGH : LOW); // Sleep 250 ms; Arduino-nRF52 core will enter low-power idle delay(250); }
How to flash (example with Adafruit nRF52840 Feather):
Bash
arduino-cli board attach arduino:mbed_nano:nano33ble arduino-cli compile --fqbn arduino:mbed_nano:nano33ble arduino-cli upload -p /dev/ttyACM0 --fqbn arduino:mbed_nano:nano33ble
If you later enable BLE or other tasks, move the LED update into a non-blocking timer or an RTOS task—logic remains identical.
That’s all you need: STAT LOW → LED ON (charging), STAT HIGH → LED OFF (full / absent).
Find MCP73831
Add green LED
Label STAT net
Pull-up resistor
329 days
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