Setting the value of timer peripheral while running

[masterLee]

Hi,

In the product specification document of nRF52840 it says that  in order to read the counter register's value I need to set the capture task  NRF_TIMER1->TASKS_CAPTURE = 1 and then I can read the timer ticks value from the corresponding CC[n]. Register. I managed to do that but  how can I do the opposite ?

How can I change the TIMER1 counter register value  while it is running  by loading it with another value since there is no such register access ?
For example if the counter register of TIMER1 has the value 0x11FFFFFF how can I change it to 0x22FFFFFF? Is it possible by assigning that value to the corresponding CC[n] register?

[Einar Thorsrud]

Hi,

You cannot set the internal counter to a specific value (except from clearing it to 0). 

[masterLee]

Any suggestions on how this can be done ( counter mode maybe)?

[Einar Thorsrud]

You cannot write to the internal counter in counter mode either (other than inputting the required amount of pulses to count to where you want to be).

What is it you want to acomplish? Can it be achieved in some other way (using an offset or something else)?

[masterLee]

I need to keep timestamps for my raw data. For this reason I have an external RTC module and the internal msec timer (TIMER1). The problem is that they come out of sync every once in a while. So I need to add subtract from the msec timer to keep RTC and Timer1 in sync.

I could use events for this but I need the microcontroller to be in sleep mode most of the time  and wake up only in certain cases.

Thank you for your help

[Einar Thorsrud]

I see. I do not have any other suggestions than using an offset that you handle in SW unfortunately, as there is simply no way to directly access the internal counter register.