11 Replies Latest reply on Jun 23, 2017 2:08 PM by Intel Corporation

    RTC pins

    DigitalOcean

      Are the RTC pins of the C1000 micro-controller mapped to any pins of the Curie Module or is the RTC crystal connected internally?

        • 1. Re: RTC pins
          Intel Corporation
          This message was posted on behalf of Intel Corporation

          Hi DigitalOcean,

          Thank you for contacting us. 

          Please take a look at https://software.intel.com/en-us/articles/intel-curie-module-datasheet . In Table 1-2 you can see the Curie signal mapping to the Quark SE C1000. There you can see the pins of the RTC of the C1000 mapped on the Curie Module.

          Let us know if this answers your questions.

          Regards,
          -Sergio A
           

          • 2. Re: RTC pins
            DigitalOcean

            Hi Sergio,

             

            In Table 1-2 if I search for the word "RTC"  I get 2 hits

             

            VCC_RTC_1P8  this is G10 of microcontroller mapped to L1 of curie module

            VSS_RTC this is H11 of microcontroller mapped to nothing.. not connected to any pin of curie module.

             

            I don't find any reference to the RTC crystal pins? Is there a crystall internally connected to the RTC pins?

            • 3. Re: RTC pins
              Intel Corporation
              This message was posted on behalf of Intel Corporation

              Hi DigitalOcean,

              I assume that your goal is to connect a XTAL to the RTC pins of the Curie, if such pins are available, is this correct? I looked deeper into the Curie datasheet. The Block Diagram doesn’t show any direct connection between XTAL inputs and RTC pins. There’s a 32 kHz Oscillator that is always running when power is applied. The notes say that its primary use is for RTC. This is internal. 
              There’s another XTAL signal which clocks at 32MHz, but there’s no mention of this being connected to any RTC signals.

              I hope you find this information useful.

              Regards,
              -Sergio A
               

              • 4. Re: RTC pins
                DigitalOcean

                Hi Sergio,

                Yes I want to use the internal RTC of the curie for timestamping purposes and so needed to know which pins should I connect the 32Khz crystal to. Or is there already a pre-generated 32.768 Khz clock that I can route to the RTC?

                 

                In section 3.2.20 of the curie datasheet it says that

                 

                The 32 kHz clock is a MEMS-based temperature-compensated clock that feeds both

                the Intel® Quark™ SE microcontroller and the Nordic* Bluetooth® low energy

                controller. It is always running when power is supplied. Its primary use is for the

                real time clock and software timer.

                so there seems there is already a clock running and I just need to use it for the RTC and I don't need to connect any external crystal to the Curie module for the RTC?

                 

                Is this right?

                • 5. Re: RTC pins
                  Intel Corporation
                  This message was posted on behalf of Intel Corporation

                  Hi DigitalOcean,

                  Thanks for your reply. I can see your point. The documentation states that the 32kHz oscillator is used primarily for the RTC but is not clear if this OSC is already routed to the RTC or if there’s certain configurations to be made. Please allow us to investigate further. We’ll contact you as soon as we have more information.

                  We appreciate your patience.

                  -Sergio A
                   

                  • 6. Re: RTC pins
                    Intel Corporation
                    This message was posted on behalf of Intel Corporation

                    Hi DigitalOcean,

                    Thank you for your patience. We have an update in regards to the oscillator. There is an internal 32kHz CLK for RTC. Please see page 79 of the linked document below for more information about the RTC Oscillator. You can also search for "CCU_RTC_CLK_DIV" for additional info on registers to change/enable RTC.

                    The datasheet of the Quark C1000 can be found here: https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/quark-c1000-datasheet.pdf .

                    Let us know if we’ve been able to answer your questions and if there’s anything else we can help you with.

                    Regards,
                    -Sergio A
                     

                    • 7. Re: RTC pins
                      Intel Corporation
                      This message was posted on behalf of Intel Corporation

                      Hi DigitalOcean,

                      Do you still need assistance with this case? 
                      Did you find useful the information from our latest reply?

                      -Sergio A
                       

                      • 8. Re: RTC pins
                        DigitalOcean

                        Hi Sergio,

                         

                        I'm still trying to understand your previous post. What you mean to say is that there is already a 32Khz clock signal generated internally for the RTC right? So there is no need to connect an external crystal.

                        I would just need some way to enable / disable the RTC to use it. I hope I'm understanding you correctly.

                         

                        I will further check the datasheet you linked up.

                        • 9. Re: RTC pins
                          Intel Corporation
                          This message was posted on behalf of Intel Corporation

                          Hi DigitalOcean,

                          Yes, we meant to say that there’s already a 32KHz clock signal generated for the RTC. I apologize if I didn’t explain this clearer before. As you know from the datasheet, there’s an internal and an external clock. If you want to use the external oscillator, you need to follow the specifications in page 79. If you want to use the internal oscillator you need to enable it. The function to do so is CCU_RTC_CLK_DIV_EN. The specifics about this signal and the clock divider can be found in page 477.

                          I hope this information is clear. Let me know if there’s anything else we can assist you with.

                          Regards,
                          -Sergio A
                           

                          • 10. Re: RTC pins
                            DigitalOcean

                            Thanks Sergio! That was really helpful.. I really appreciate it.

                            • 11. Re: RTC pins
                              Intel Corporation
                              This message was posted on behalf of Intel Corporation

                              You’re welcome! It’s great to hear you found our reply to be helpful. Don’t hesitate to come back if help is needed.

                              Regards,
                              -Sergio A