Brown Out event will reset the PSoC 4 device (BOR).
A brown out event can be of two types:
Retention Brownout Reset: If VCCD dips below the minimum logic operating voltage, but not below the minimum logic retention voltage.
Non Retention Brown out event: If the VCCD dips below the minimum logic retention voltage (specifications given in the datasheet of the device: https://www.cypress.com/file/138651/download ).
It is possible to differentiate Retention Brownout Reset by using a special register, PWR_BOD_KEY. The PWR_BOD_KEY register only changes value when written by firmware or when a non-retention reset such as a non-retention BOD, XRES, or POR event.
It is not possible to distinguish non retention BOD, XRES or POR events using on chip resources.
For more details on this, please refer to the 'Identifying Reset Sources' section of the Architecture TRM: https://www.cypress.com/file/126171/download
Refer to the register TRM for details on PWR_BOD_KEY register and RES_CAUSE register: https://www.cypress.com/file/122336/download
Thank you for your reply.