You should be able to do exactly what you tried to do; that was one of the intents with os_cputime. Hopefully I will have an answer soon regarding why this does not work.
Regarding timers: The nimble stack on the nrf52 currently uses Timer 0 for cputime (and thus for the controller BLE timing). It either uses RTC1 or TIMER1 for the os tick, depending on the syscfg variable XTAL_32768 in your bsp syscfg.yml file. > On Jan 8, 2017, at 6:20 PM, WangJiacheng <[email protected]> wrote: > > Hi, Will, > > Thanks a lot for your reply. > > Yes，the hardwear processor clock frequency of nRF52 (Cortex M4F) is 64 MHz > and can not be changed. > > The reason of changing CLOCK_FREQ is that I want re-use the internal timing > of mynewt already there with more accurate timing, by calling function > "os_cputime_get32()”. I’m trying to implement a (soft) IC card reader by > nRF52 with mynewt OS and nimble stack running. > > I am also considering to use an independent timer (NRF_TIMER3 or NRF_TIMER4) > at the cost of about 0.1mA current. I already use NRF_TIMER2 to provide a 4 > MHz clock signal output from GPIO of nRF52. By reading the source code of > apache-mynewt-core, my understanding is that NRF_TIMER0 and NRF_TIMER1 is > already used by mynewt OS and nimble stack, is my understanding correct? > > Thanks, > > Jiacheng > >> 在 2017年1月9日，01:10，will sanfilippo <[email protected]> 写道： >> >> Those should be the only two parameters you need to configure. Must be a bug >> in the controller :-) >> >> I think it is worthwhile to point out that CLOCK_FREQ only changes the units >> of os cputime; it does not affect the speed at which the processor runs. At >> least, I could not see any other uses of CLOCK_FREQ. So, these settings only >> affect the nimble stack and the controller specifically (internal controller >> timing). >> >> I am curious why you wanted to change this variable; what were you trying to >> achieve? >> >> Thanks for pointing this out; I will take a look to see why it is not >> working. >> >>> On Jan 7, 2017, at 10:48 PM, WangJiacheng <[email protected]> wrote: >>> >>> Hi, >>> >>> The default CPU time frequency of Mynewt OS and Nimble stack is 1 MHz, I >>> try to change the CPU time frequency to be 2 MHz, I modified the related 2 >>> config files: >>> configure file “hw/bsp/nrf52dk/syscfg.yml” as >>> CLOCK_FREQ: >>> description: 'TBD' >>> value: 2000000 >>> configure file “kernel/os/syscfg.yml” as >>> OS_CPUTIME_FREQ: >>> description: 'Frequency of os cputime' >>> value: 2000000 >>> >>> The app “bleperiph" is running and the CPU time frequency is 2 MHz, also >>> the BLE “nimble-bleprph” peripheral can be scanned by LightBlue of iOS >>> APP, and show 1 service is there. However, when I try to connect it ,an >>> error massage “Connection Alert: Timeout interrogating the peripheral” >>> >>> When change back above 2 syscfg parameters to 1000000, it can be connected. >>> >>> And app “bletiny” is the same. >>> >>> Is there any missed config setting in my test? How to change the CPU time >>> frequency to 2 Mhz and Nimble device can be connected? >>> >>> Thanks, >>> >>> Jiacheng >>> >>> >> >
