SparkFun Electronics Forum

Hi. I m using Arduino Mega 2560 R3 which has an AVR processor. My 5V Mega is interfacing with a HC-05 bluetooth umm card! I am using a basic voltage divider with 1k and 2k to reduce 5v signal to 3.3v signal from Tx of arduino to Rx of hc-05. And it works fine as far. As far as i am aware of level shifters that has umm transistors so i m thinking to use a level shifter to reduce ( or increase for future projects) the signal voltage in Proper Way. I saw some bi-directional level shifters. Some of them just have transistors like bss138 and some resistors. And they say its a bit sluggish.so they offer umm circuit type level shifters which have TXB0108 and 74HCT245 and so on.. no one wants to have a sluggish signals. So i thinkimg to use circuit for this level shifting. I sae in a site that AVR chips dont work good one of that 2 ( TXB0108 - 74HCT245 ). anyone has information about that compitability issue?

For example Teensy has ARM and they use 74HCT245 for level shifting on their board for teensy add-on. That means 74hct245 is compitable with ARM chip. But my mega has AVR.. which one is compitable for AVR.. because i saw one of them is not and i cant rememebee that website.

Realy?no one has any info about AVR processors and IC type level shifters compitability?

Seems like this product from Sparkfun would work for you and it's bi-directional.
https://www.sparkfun.com/products/12009

So here is a link that compares the different level shifters [quote]http://happyinmotion.com/?p=1247/quote] and I see the a reference to the MOSFET signal being less that optimal for high speed stuff.

ARM vs. AVR? I would think that only the speed of the signal that you are trying to level shift would matter and how well a particular implementation of level shifting responds and reproduces that signal shifted.

Thx for ur interest but this kind of basic 1 transistor - 2 resistor styles are defined as sluggish! So i try to choose a Chip like TXB or 74htc