You are developing a cardiac monitor that must trigger an alarm within 50 ms of detecting an abnormal rhythm. A last‑minute hardware change reduces the ADC sampling rate by 20%. Describe how you would identify bottlenecks, prioritize tasks, and adjust the firmware to maintain the 50 ms deadline under this new constraint.

Use the CIRCLES framework: Clarify the 50 ms latency requirement, Identify constraints (ADC rate drop, CPU load), Recommend solutions (DMA offload, reduce ADC resolution, raise alarm task priority, enable tickless idle), Communicate trade‑offs (resolution vs. timing), List implementation steps (profile latency, adjust ISR priorities, test with new hardware), Evaluate results (measure latency under load), Summarize deterministic behavior. (≈130 words)

To address the 50 ms alarm latency under a reduced ADC sampling rate, I first clarified the critical requirement: the alarm must trigger within 50 ms of detecting an abnormal rhythm. I identified the bottlenecks: the ADC’s lower throughput increased the time between samples, and the current polling‑based processing added unnecessary CPU load. I recommended a multi‑pronged solution: 1) Offload the bulk of the signal acquisition to a DMA engine to free the CPU; 2) Reduce the ADC resolution from 16‑bit to 12‑bit where clinically acceptable, cutting conversion time; 3) Increase the priority of the alarm task in the RTOS and enable tickless idle to reduce interrupt latency; 4) Replace polling loops with interrupt‑driven callbacks to avoid wasted cycles. I communicated the trade‑offs—slight loss of resolution versus guaranteed deterministic timing—and implemented the changes in a modular way. After profiling, the alarm latency dropped to 42 ms, and the system maintained data integrity, satisfying both safety and performance criteria. (≈190 words)