Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

PSoC™ 6 Forum Discussions

Vivek_DiehlCont
Level 1
Level 1
Welcome! First question asked First like given

I want to use a Capacitive sensor touch button as ON/OFF button with PSoC 6. Therefore I wanted to check whether it is possible with PSoC 6.

From Reference manual, I can see that CSD interrupt is not supported as wakeup source.

Is there any way by which we can use low power comparator with Capacitive Touch Sensor to wakeup from Sleepmode?

0 Likes
1 Solution
Hari
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hi viku_4830896

CapSense sensing requires the CPU to process the states and therefore, cannot have the CPU in sleep mode. Note that while the actual scanning is happening, the CPU can be in sleep mode and CapSense interrupt can wake the device up.

If you see the CapSense configurator, it will mention the duration it takes for scanning the sensors and in this time, the CPU can be in sleep mode.

pastedImage_0.png

If your requirement is deep-sleep, then the CapSense peripheral will not be able to wake the CPU from deep sleep.

An alternate option that is widely used is to use a WDT to wake the CPU periodically and initiate a CapSense scan. This way, the CPU needs to be active for a very small duration - let's say 5ms with WDT configured to wake the CPU every 100ms. This means that the WDT will wake the CPU every once 100ms for a 5ms duration. If a touch is detected, the rest of the functions can be performed.

Best regards,
Hari

View solution in original post

1 Reply
Hari
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hi viku_4830896

CapSense sensing requires the CPU to process the states and therefore, cannot have the CPU in sleep mode. Note that while the actual scanning is happening, the CPU can be in sleep mode and CapSense interrupt can wake the device up.

If you see the CapSense configurator, it will mention the duration it takes for scanning the sensors and in this time, the CPU can be in sleep mode.

pastedImage_0.png

If your requirement is deep-sleep, then the CapSense peripheral will not be able to wake the CPU from deep sleep.

An alternate option that is widely used is to use a WDT to wake the CPU periodically and initiate a CapSense scan. This way, the CPU needs to be active for a very small duration - let's say 5ms with WDT configured to wake the CPU every 100ms. This means that the WDT will wake the CPU every once 100ms for a 5ms duration. If a touch is detected, the rest of the functions can be performed.

Best regards,
Hari