Chaining Two 16-bit LP timers

[Jumshed Akhtar]

Hi, I have configured two 16-bit general purpose timers in master slave mode and made 32 bit timer to get the time base ranging from micro seconds to minutes. I want to configure two 16-bit LP timers to wake up the system after for specified time ranging from micro seconds to minutes to have very low power system. Could you please suggest me some design ways to do this with LP timers as there is no way to have master slave in LP timers. I am using stm32l46x.

Thank in advance 😀

[waclawek.jan]

You could cascade two LPTimers at the cost of two pins, interconnecting them externally.

But do you need such a granularity at long times that you can't pull this out using just one LPTim, utiilzing its the prescaler, and/or perhaps switching between different internal clock sources?

JW

[Jumshed Akhtar]

Jan,

Now I have final board, difficult to connect them. You can explain me that method little bit more, for information. May be in future, can be done in that way.

One LPtim is not enough it gives very small interval and also resolution is important as well. I need to put it in sleep from milli seconds to hours. But resolution of micro seconds is required.

[waclawek.jan]

Replacing the internal connection, one LPTIM would be set to output pulses, and the other would be set to external clock, being clocked by those pulses from the first LPTIM.

Couldn't RTC be used for this purpose?

JW

[Jumshed Akhtar]

Thanks for your response.

RTC and wake up timer of RTC module, I explored in detail.

1- I want to use RTC as a real timer utc time keeper even in low power mode as it is with 1Hz resolution

2- If I change RTC to more resolution than 1Hz then, it will be very fast and may not act as a real timer utc time keeper and may be I can get time from that and convert back by scaling it but that part seems me tricky as conversion sec, minute, dates:many corner cases .