1
\$\begingroup\$

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.

\$\endgroup\$
3
  • 1
    \$\begingroup\$ Connect reset to Vcc then unconnect it. \$\endgroup\$
    – Andy aka
    Apr 1, 2015 at 17:11
  • \$\begingroup\$ Thank you. The EN pin should be connected to pull up resistor? \$\endgroup\$
    – yaya
    Apr 1, 2015 at 18:15
  • \$\begingroup\$ No, because it has a pull-down resistor \$\endgroup\$
    – Andy aka
    Apr 1, 2015 at 20:20

2 Answers 2

2
\$\begingroup\$

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

schematic

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.

\$\endgroup\$
1
  • \$\begingroup\$ Thank you. That is very usefull..The EN pin should be connected to pull up resistor? \$\endgroup\$
    – yaya
    Apr 1, 2015 at 18:18
0
\$\begingroup\$

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.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.