Connecting Rx and Tx with ckts having different supplies?

[bimbla]

How do I connect Rx and Tx (both unidirectional) from a ckt powered by 3.3V to Tx and Rx of a ckt powered by 5V?

Can we achieve it using simple transistors?

Kindly discuss your schemes.

bimbla.

 

[miniyash21]

Re: Connecting Rx and Tx with ckts having different supplies

NO you cannot use transistors. Connect the Rx and Tx of +5v powered ckt to the buffer(74HC125).It will output the signals at 3.3 v to the ckt powered by 3.3V.

 

[mandrei]

Re: Connecting Rx and Tx with ckts having different supplies

Also You can put a diode from 5V output (Tx) to 3.3V supply.
Thos is a classic solution to protect a 3.3V imput from a 5V output.

 

[7rots51]

Re: Connecting Rx and Tx with ckts having different supplies

you can level converters chips from TI (74LVC series) and Maxim.

check their websites.