- It is possible to use an external 1PPS signal to drive the RTC, please see this thread for the implementation, http://secure.cypress.com/?app=forum&id=2233&rID=51134 .
- Modifying the component in a project is local to your project. It will not affect the actual RTC component. The component can be reused in its original form in other projects.
I hope this helps.
The 32.768 KHz external crystal oscillator can be used by checking the "XTAL32kHz" tab in the "Configure System Clocks" dialog box which is found in the "Clocks" tab of .cydwr file.
Thanks for the suggestions, I forgot to mention I cannot use the XTAL 32 pins because I have the first touch kit, which has these reserved pins mapped to the pushbutton switch and one of the accelerometer control pins.
If I do not have the 32kHz watch crystal enabled I get this error:
"The 32KHz watch crystal is not enabled and must be active for the one pulse per second interrupt to function.
The one pulse per second interrupt from the PM system requires the 32KHz crystal to be enabled. Review and update the 32KHz clock your design and rebuild."
If I enable it, its also not happy:
"Pin Error: (Invalid pin assignment. This pin has been reserved for use by the 'XTAL 32kHz' clock.).
A pin assignment is currently in an error state."
I tried adding the generated RTC source (from a different workspace) to the project directly, but then it would not compile as it could not find "cyPm.h: No such file or directory "
Using RTC component with External 32.768kHz crystal would be difficult on First Touch Kit if you are planning to use even the Accelerometer present on the board.
For this purpose, one solution would be to use the APIs generated from an RTC component into the the project without actually using an RTC component.
In such a case, external 1PPS signal is required for the RTC functionality to be implemented.