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CC1110 Real time clock using 32.768KHz crystal problem

sumanth kashyap
Prodigy 30 points

Hi


I need help regarding CC1110F32 Real time Clock generation.

Let me explain you little info about this

  1. I have around 50+ ( FIFTY PLUS) CC1110 Modules ( Perfectly working and genuine )
  2. Where I'm running custom TCP/IP stack and ISM 868Mhz custom radio communication stack which is communicating with LAN/WAN via router.
  3. Currently I'm not bothered about power saving modes(none of my devices will never sleep).
  4. All GPIO's are connected to external devices. ( Please do not suggest me to use external RTC IC's after reading my Qns).
  5. Using NTP I'm able to synchronize and storing real time in a variable. ( I can re- sync NTP only after 72Hours)
  6. My engineers are trying with 26Mhz clock with timers which are highly inaccurate reading I'm observing.( failed to get proper timer running)

Now I want to keep a timer running which should be accurate. I have 26Mhz  clock and  32.768Khz crystal on board. I will be happy with 1-2 min deviation for every 72hours.

Is it possible to use 32.768Khz crystal to run a timer which can keep my real time running always.( ** My devices will never sleep)  independently and i should be able to use other CC1110F32 features ruining at 26Mhz clock.( Radio + SPI+ PWM+ software I2C+ ADC will be always on)

Please can anybody guide me how can i use 32.768Khz Crystal to run a timer accurately ( Please do not tell me to re-syn real time Using NTP which is there in my software)

Please let me know if any info is required from my side. If its not possible I may have to switch to some other SOC. Its urgent Please Guide me how i can handle this.

Regards

Sumanth Kashyap H R

  • 0
    Prodigy 240 points
    You can use Sleep Timer and 32768 crystal. Datasheet states that Sleep Timer must not be used in active mode. You can use it but with care. In active mode there is a chance that STIF will not be set (you can search forum - it is related to disabling global interrupt). So you will be safe if periodically check something like: if( (WORIRQ & 0x11) == 0x11) { STIF = 1; }.