Reset IC Buffer manually

Question

I have a buffer which I want to reset. The EN pin is connected to a pull upp resistor while the Reset pin is connected to pull down resistor. What should I do to reset the buffer manually? Should i connect the reset to pull upp resistor to Reset the buffer?

Thanks in advance.

Answer 1

A PNP transistor or P-channel MOSFET can be used as a switch to temporarily connect the RESET signal to Vcc.

^{simulate this circuit – Schematic created using CircuitLab}

Note that this arrangement inverts the operation of the RESET pin, so setting RESET# to LOW sets the RESET pin to HIGH. If you want to re-invert it again to keep the same polarity, you can do so with a simple NPN transistor.

Answer 2

You don't define the component you are using therefore it is difficult to know how to safely drive the inputs. You must look at the input specifications. The input on many CMOS components don't have default input states if the input if left floating. Those types of inputs can be connected directly to Vcc or Vss. If they come up with the default state defined then when you drive them directly they will draw current related to their input impedance. If that current is not acceptable to your design than add resisters to limit current to acceptable level. Also if you are using CMOS logic components you may be able to directly drive the reset input.