I am building a UART 3.3V to 5V Level translator between a Raspberry Pi and a ATMega328.
The 74HCT244 is my choice of translator but I can't find a good example of of hooking it up.
- Am I right that I should power it with 3.3V(VCC)?
- Output enabled(Grounded)
- 3.3v TX on Input 1.This should Output 1 at 3.3V to the ATMega328 that can work with 3.3V logic.
- 5v RX on Input 2 with Output Enabled. Connecting Output 2 at 3.3V to the RPI.
Number 4 to me is the bit I am not certain about. If I run the VCC at 3.3V will the input pins accept voltages above VCC.
Best Answer
Instead of the 74HCT744, you could use a chip specially made for this, such as the TI TXB0104. SparkFun makes a convenient breakout board for this chip, priced at only $4, so you don't have to deal with as SMT part.
From the SparkFun description:
So you want to supply VCCA with 3.3v and VCCB with 5v.