How to convert 5V PIC16F877 output to 3.3V using resistors?

[zahidkhan]

I am using PIC 16F877 and i want to convert the 5V output from one ot its pins to 3.3V using resistors.how should i do it. i need to know the value of resistor and how to calculate it.
regards...

 

[IanP]

Re: steping down 5V

I don't know what are you going to connect to this 3.3V point, but much better idea than 2 resistors is to use a 3.3V zener diode and, say, 1kΩ resistor between the 5V pin and 3.3V output ..
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/zenereg.html
Regards,
IanP

 

[zahidkhan]

Re: steping down 5V

thanks IanP. actually i am using Lassen iQ GPS Module.which operates at 3.3V.i want to communicate with its serial ports through pic. this is the whole scenario.

 

[IanP]

Re: steping down 5V

In this instance 1kΩ resistors and 3.3V zener diodes should do the job ..

Regards,
IanP

 

[CM600]

Re: steping down 5V

You can do it with optoisolator like PC816.

 

[davemaster]

Re: steping down 5V

thanks IanP. actually i am using Lassen iQ GPS Module.which operates at 3.3V.i want to communicate with its serial ports through pic. this is the whole scenario.

Greetings,

Just use a couple of resistors to build a voltage divider.

Exp.

In Fig.

Vo = (5V*2.2k)/3.4k ~ 3.3V --> Vo=V*R2/(R1+R2)

Chage this according the resistors values in your hands.

Good Luck.