Hi,
In deep-sleep mode, the high-frequency clocks and peripherals that require high-frequency clocks are disabled. Since CapSense requires high frequency clock, it cannot be used in Deep-Sleep mode.
The high-frequency clocks include the internal main oscillator (IMO), external crystal oscillator (ECO), and phase-locked loops (PLLs). The internal low-speed oscillator (ILO) clock remains active and can be used to clock the watchdog timer (WDT), which can be used as a sleep timer to wake the system from deep-sleep. Some PSoC 4 devices also have an option to include a watch crystal oscillator (WCO) that can operate during deep-sleep. For more details please refer to https://www.infineon.com/dgdl/Infineon-AN86233_PSoC_4_and_PSoC_Analog_Coprocessor_LowPower_Modes_and...
You can also have an interrupt to wake MCU up from deep sleep and then you can use Capsense.
Furthermore, Sleep mode should be used when peripherals such as the ADC, CAPSENSE™, digital communication, or others must remain active, but CPU activity is not required. This can reduce current consumption between events such as ADC conversions and digital communication transactions. For more details please refer to https://www.infineon.com/dgdl/Infineon-AN86233_PSoC_4_and_PSoC_Analog_Coprocessor_LowPower_Modes_and...
Please refer to code example https://www.infineon.com/dgdl/Infineon-CE210291-Code%20Example-v04_00-EN.zip?fileId=8ac78c8c7cdc391c...
Kind Regards
Arpit Srivastav
