Dear Nordic Support Team,
We have a system where an MCU is connected to a Wi-Fi module operating in NCP (Network Co-Processor) mode. The MCU controls the Wi-Fi chip to connect to an MQTT broker, subscribe to topics, and publish messages periodically.
We are using the Nordic Power Profiler Kit II (PPK2) in Ampere meter mode, connected in series with our device to measure current consumption.
Issue:
When running our system with PPK2, the device initially works correctly—MQTT connects, messages are received, and the Wi-Fi chip wakes up once every second as expected. However, after a period of time, the system stops working at random intervals — sometimes after 4.5 minutes, other times after just 10 to 30 seconds.
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The periodic current spikes indicating Wi-Fi wake-ups disappear
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No MQTT messages are received
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The system seems to stop functioning entirely
This issue only happens when using PPK2. If we remove the PPK2, or use a Keysight N6705C to measure current instead, the system continues to operate normally, with regular 1-second wakeups.
The screenshot below is from the PPK2 measurement software, showing the current profile. As you can see, in this particular run, the current suddenly drops after about 4 minutes and 30 seconds, and the system stops its periodic wakeups.
Question:
Why does using the PPK2 cause the system to stop working?
Best regards,
Gray