cancel
Showing results for 
Search instead for 
Did you mean: 

PSoC 4 MCU

DaHu_285096
Contributor II

I have a project where one of the IC need 31.25kHz oscillation to operate.

Until now I used a crystal on that device and used 4200 micro as my host controller. For low power I put the controller to deep sleep and it was woken up by interrupt from the other device.

Because the crystal is getting harder to source I wanted to generate the 31.25kHz from the controller. Because 4200 I was using only had 2% accuracy due to RC operation, I changed model to 4200 L and connected 24MHz crystal.

Using a PWM output to pin, the 31.25Khz signal is generated and the circuit works. However, I need to put the micro into a deep sleep mode to increase battery run time.

How can I keep the 31.25kHz running while 4200L is deep sleep and also, how can I get it ti wake periodically (every 1 second) to perform some non-interrupt functions that need to be done?

Thanks

0 Likes
1 Solution
Ekta
Moderator
Moderator

Hello DaHu_285096

PSoC 4200L in Deep Sleep mode will not support a 24MHz clock which you are using for generating the 31.25kHz signal through PWM . Also other peripherals are in Retention mode. The PSoC 4 Low power mode and power retention technique mentions this : https://www.cypress.com/documentation/application-notes/an86233-psoc-4-low-power-modes-and-power-red...

pastedImage_0.png

Is it possible for you to use the WCO  (which is 32.768-kHz watch crystal) for your operation ?

You can enter the Deep Sleep mode using the CySysPmDeepSleep().

Exit from Deep Sleep mode occurs when an interrupt is triggered. Upon exiting Deep Sleep, PSoC re-enters Active mode. The configuration of Deep Sleep wakeup sources requires only that their interrupts be enabled.  Then you can perform the desired functions and reenter the Deep Sleep mode using the same API.

You can use the following sources to wake up from Deep Sleep every one ms.

pastedImage_0.png

Regards

Ekta

View solution in original post

0 Likes
3 Replies
Ekta
Moderator
Moderator

Hello DaHu_285096

PSoC 4200L in Deep Sleep mode will not support a 24MHz clock which you are using for generating the 31.25kHz signal through PWM . Also other peripherals are in Retention mode. The PSoC 4 Low power mode and power retention technique mentions this : https://www.cypress.com/documentation/application-notes/an86233-psoc-4-low-power-modes-and-power-red...

pastedImage_0.png

Is it possible for you to use the WCO  (which is 32.768-kHz watch crystal) for your operation ?

You can enter the Deep Sleep mode using the CySysPmDeepSleep().

Exit from Deep Sleep mode occurs when an interrupt is triggered. Upon exiting Deep Sleep, PSoC re-enters Active mode. The configuration of Deep Sleep wakeup sources requires only that their interrupts be enabled.  Then you can perform the desired functions and reenter the Deep Sleep mode using the same API.

You can use the following sources to wake up from Deep Sleep every one ms.

pastedImage_0.png

Regards

Ekta

View solution in original post

0 Likes
odissey1
Honored Contributor II

DaHu,

When using P4200 w/o 24MHz XTAL, have you been able to use Deep sleep mode?

/odissey1

0 Likes
Len_CONSULTRON
Honored Contributor II

DaHu,

As Ekta indicated, the ECO (24MHz crystal oscillator) is not available in Deep Sleep mode.  It is in Sleep mode.

I don't know which device you are using that needs 31.25KHz.  Can it use 32.768KHz instead?  If so, the WCO (32KHz watch crystal oscillator) is available in Depp Sleep mode.

Len

Len
"Engineering is an Art. The Art of Compromise."
0 Likes