We’re trying to optimize power consumption of HCM111Z for our application.
We are stopping advertisements depending on external interrupt. We are expecting lowest power consumption. But we observed the device is waking up every 20 seconds and may be doing some bookkeeping activities or so, and sleeping again without any BLE advertisements. But this waking up is consuming 5mA current. Which is increasing the total average sleep current to high. Could you please let me know what is the purpose of this periodic wakeup and if there is a way to control this waking up period or stopping it entirely.
Hi Vamsi,
Can I know if you are currently using QuecOpen solution or AT Standard Firmware?
Regarding the issue, will reply once i discussed with the internal team.
QuecOpen solution provided by Quectel team in India.
Regarding the 20-second wake-up issue, this interval is a hard-coded limit within the HCM111Z protocol stack used for internal housekeeping and synchronization. While you can technically “disable” this specific 20-second trigger by setting a manual timer, the workaround requires the new timer to be shorter than 20 seconds. This effectively forces the chip to wake up more frequently, which would unfortunately increase, rather than decrease, the average power consumption. Therefore, unless the 20-second wake-up is interfering with specific logic, keeping the default interval is better for the battery than forcing a shorter cycle.
Regarding Shutdown Mode, while system_power_off() offers the absolute lowest power consumption by cutting power to the CPU domain, it is highly sensitive and functionally equivalent to a full system reset upon wake-up. However, the PMU (Power Management Unit) wake-up pins are extremely sensitive to even minor electrical noise, which often leads to the “immediate restarting” issue the customer observed. Because this mode requires very strict hardware conditions and restarts all software from scratch, it is generally recommended to use ql_sys_sleep_enable() instead. This allows for a stable sleep state that is easier to manage via external interrupts without the volatility of a full shutdown.
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