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.
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?
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.
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?
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.
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.
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.
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.