Interrupt Handling

The driver keeps default behavior in serviceAllInterrupts() (updates global flags), and also supports user callbacks. For most sketches, prefer update() in loop(). It services pending IRQs, drains enabled FIFOs, reads RTOR when configured, and falls back to serviceAllInterrupts() when needed. Use servicePendingInterrupts() directly only in lower-level custom loops where you want interrupt servicing without the rest of the normal update() data-path work.

Interrupt Usage

Wire MAX30001G INTB (and optional INT2B) to interrupt-capable GPIO pins and pass those pins to the constructor.

const uint8_t AFE_CS_PIN  = 10;
const int AFE_INT1_PIN = 2;   // INTB
const int AFE_INT2_PIN = -1;  // INT2B optional, -1 if unused
 
MAX30001G afe(AFE_CS_PIN, AFE_INT1_PIN, AFE_INT2_PIN);
 
void setup() {
  // Constructor attaches ISR handlers for valid interrupt pins.
  // Choose which status events drive INT1/INT2:
  afe.setInterrupt1(true,  true,  true,  false, false);  // ECG + BIOZ + RTOR on INT1
  afe.setInterrupt2(false, false, false, false, false);  // INT2 disabled
}
 
void loop() {
  if (afe.update()) {
    // Interrupts were serviced and configured data paths were drained.
    // Read ECG_data / BIOZ_data / RTOR_data here as needed.
  }
}

servicePendingInterrupts() uses Arduino core APIs noInterrupts() and interrupts() to atomically read/clear the software pending flags. These APIs are available on AVR, SAMD, ESP8266, and ESP32 Arduino cores, so no API change is needed for ESP-type boards.

If your board does not wire interrupt pins, update() falls back to serviceAllInterrupts(). If you are not using update(), call serviceAllInterrupts() periodically instead. If you provide your own ISR, set library globals afe_irq_pending and afe_irq1_pending/afe_irq2_pending (do not use a separate local pending flag). If you use latched event/fault globals, clear them explicitly with clearLatchedStatusFlags() after handling.

Configure which events drive INT1/INT2

setInterrupt1(...) and setInterrupt2(...) program MAX30001G EN_INT1 and EN_INT2.

Example:

// INT1: ECG + BIOZ FIFO related interrupts
afe.setInterrupt1(true,  true,  false, false, false);
// INT2: R-to-R interrupt
afe.setInterrupt2(false, false, true,  false, false);

Available per-event callbacks (<tt>InterruptEvent</tt>)

• MAX30001G::IRQ_ECG_FIFO -> MAX30001_STATUS_EINT
• MAX30001G::IRQ_ECG_OVF -> MAX30001_STATUS_EOVF
• MAX30001G::IRQ_ECG_FAST -> MAX30001_STATUS_FSTINT
• MAX30001G::IRQ_ECG_LEADOFF -> MAX30001_STATUS_DCLOFFINT
• MAX30001G::IRQ_BIOZ_FIFO -> MAX30001_STATUS_BINT
• MAX30001G::IRQ_BIOZ_OVF -> MAX30001_STATUS_BOVF
• MAX30001G::IRQ_BIOZ_OVER -> MAX30001_STATUS_BOVER
• MAX30001G::IRQ_BIOZ_UNDER -> MAX30001_STATUS_BUNDR
• MAX30001G::IRQ_BIOZ_CGMON -> MAX30001_STATUS_BCGMON
• MAX30001G::IRQ_LEADS_ON -> MAX30001_STATUS_LONINT
• MAX30001G::IRQ_RTOR -> MAX30001_STATUS_RRINT
• MAX30001G::IRQ_PLL_UNLOCK -> MAX30001_STATUS_PLLINT

Example: Individual ECG and BIOZ FIFO callbacks

void onEcgFifo(MAX30001G* dev, uint32_t status, void* ctx) {
  (void)status;
  (void)ctx;
  dev->handleECGFifoInterrupt(false);   // pushes samples into global ECG_data
}
 
void onBiozFifo(MAX30001G* dev, uint32_t status, void* ctx) {
  (void)status;
  (void)ctx;
  dev->handleBIOZFifoInterrupt(false);  // pushes samples into global BIOZ_data
}
 
void setup() {
  afe.setInterruptEventCallback(MAX30001G::IRQ_ECG_FIFO,  onEcgFifo);
  afe.setInterruptEventCallback(MAX30001G::IRQ_BIOZ_FIFO, onBiozFifo);
}

Example: One aggregate callback

void onAfeAggregate(MAX30001G* dev, uint32_t status, void* ctx) {
  (void)ctx;
 
  if (status & MAX30001_STATUS_EINT)  { dev->handleECGFifoInterrupt(false); }
  if (status & MAX30001_STATUS_BINT)  { dev->handleBIOZFifoInterrupt(false); }
  if (status & MAX30001_STATUS_RRINT) { dev->handleRtoRInterrupt(); }
}
 
void setup() {
  const uint32_t mask = MAX30001_STATUS_EINT | MAX30001_STATUS_BINT | MAX30001_STATUS_RRINT;
  afe.setInterruptAggregateCallback(onAfeAggregate, nullptr, mask);
}

If aggregate and individual callbacks are both registered, aggregate runs first.

Interrupt Callback API summary

• setInterruptEventCallback(event, cb, context)
• clearInterruptEventCallback(event)
• setInterruptAggregateCallback(cb, context, statusMask)
• clearInterruptAggregateCallback()
• clearAllInterruptCallbacks()
• clearLatchedStatusFlags()