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PSoC™ Creator & Designer Forum Discussions

Anonymous
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Hi, I bought a CY8CKIT-043 and I'm trying to run the example project "RTC_P4_WDT_Example01" that showcases RTC usage along with low power operation (deep sleep).

   

The problem is I get the time to display once and then nothing happens anymore. I looked in the documentation and I just seem to find that maybe the crystal required (32.768KHz) is not included in the SoC, is that the case? 

   

 

   

I tried finding where the code stops by using some breakpoints and it seems that it can't get passed the "EnableRtcOperation" function completely. I uploaded the main code that can be found in example projects for PSOC 4 but I could not upload the .c file so the formatting may be a little weird sorry for that. 

   

 

   

Else, would anyone have an idea of what could cause the problem?

   

 

   

Thanks in advance!

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1 Solution
Bob_Marlowe
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Welcome in the forum!

   

In deep sleep the ILO frequency will be up to 60% off without a clock crystal. Not quite usable for an RTC.

   

 

   

Bob

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Anonymous
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I'm also sorry if this was not posted in the right section of the forum. It it's the case, please kindly indicate and I'll move it to the appropriate section.

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Bob_Marlowe
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Welcome in the forum!

   

In deep sleep the ILO frequency will be up to 60% off without a clock crystal. Not quite usable for an RTC.

   

 

   

Bob

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Anonymous
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Hi Bob, thanks for taking the time to answer me. 

   

With this project, the goal is to switch to WCO instead of ILO except if there's something I didn't quite understand correctly. 

   

As of my readings on documention for PSoC 4200M family, the WCO is supposed to be included 

   

"Clock System

   

The PSoC 4200-M clock system is responsible for providing clocks to all subsystems that require clocks and for switching between different clock sources without glitching. In addition, the clock system ensures that no meta-stable conditions occur. The clock system for the PSoC 4200-M consists of a Watch Crystal Oscillator (WCO) running at 32 kHz, the IMO (3 to 48 MHz) and the ILO (32-kHz nominal) internal oscillators, and provision for an external clock."

   

 

   

On the same page, we can read the following:

   

"Crystal Oscillator

   

The PSoC 4200M clock subsystem also includes a low-frequency crystal oscillator (32-kHz WCO) that is available during the Deep Sleep mode and can be used for Real-Time Clock (RTC) and Watchdog Timer applications."

   

 

   

Which seems to point that there should be all required parts included in the SoC no?

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Bob_Marlowe
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You refer to the description of the PSoC4 M chip which provides all the needed connections (pins) for a WCO.  The letter "C" stands for "Crystal" which is never integrated into a chip but is an external component.

   

Talking about the prototype board you bought, there is a lot of documentation including a schematic. Look at "Program Files (x86)\Cypress\ Here you find entries for all your installed kits. In the schematic .pdf file I couldn't find any crystal, so you would have to connect a watch crystal (with some caps) externally. See excerpt from schematic, you just have to connect the xtal between P0_5 and P0_5.

   

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Bob

   

Anonymous
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Ok thanks for clarifying the documentation. It's the "The PSoC 4200M clock subsystem also includes a low-frequency crystal oscillator (32-kHz WCO) " that got me confused but effectively I thought that I would need an external crystal and you just confirmed it. 

   

 

   

Thank you again for the answers you provided. 

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Bob_Marlowe
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You are always welcome!

   

 

   

Bob

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