using voltage supervisior or internal

[Electro nS]

hello guys

simple question : i plan to use PIC18 or Atmega328 in an important project and i need to know the difference in using built-in/internal POR and BOR and watchdog versus using external IC specified for this purpose called voltage supervisors like MCP130 and similar ICs.


please give some explanation and recommendations and if there is possible reference on your answer

regards

 

[Analog Ground]

1. Some external supervisors will monitor more than one voltage. This feature can insure that circuitry around the microcontroller is also ready to go before the microcontroller starts up.
2. External supervisors frequently have an input from a reset switch which can be used with a mechanical switch or some other source of reset. The circuit usually includes switch debounce. A variation is a short switch contact will cause a "soft" reset and a longer switch contact will cause a "hard" reset. The former is typically used to signal the program and the later is used to perform a complete reset of the device.
3. A reset from an external supervisor can also reset other stuff along with the microcontroller.