Re: can you introduce power on reset for me,what the use of
POR ensures that a system is kept in reset at power up, until the voltage reaches a level sufficient for correct operation of the system.
At power up, the voltage rises from zero to the nominal. Thus, the POR ensures that devices are held in reset until the voltage rises above the guaranteed minimum. That way, the system is only allowed to start up when there is no danger of malfunction due to insufficient supply voltage.
For example, if your system power is 5V, usually the devices in it will work properly down to 4.75 or even 4.5V, but no one can guarantee that they will operate properly below that voltage. The POR will release the reset line when the supply voltage is above 4.75V, for example.