Description

Most of our customers like to use the Arduino for prototyping, design and invention, but they often find themselves stuck when connecting the Arduino card to the latest sensors, displays, controllers, interfaces, etc., as they almost all work in 3.3V logic.

This circuit solves the problem of the interface of 3.3V logic peripherals with a 5.0V logic circuit such as the Arduino. Most 3.3V devices don't like to be connected with 5V signals and can damage or even grill them. The 74LVC245 circuit is designed so that it works from 1.8V, it always accepts 5V signals in one pin and converts it to a lower logic level on the opposite pin. This circuitry works only with digital signals, it does not convert analog signals (you need an operational amplifier for this). It has 8 channels, but will not work with bi-directional or pull-up devices such as I2C or 1-Wire. It works well for SPI, Serial, Parallele buses and other logical interfaces.

It is easy to use. We suggest that you consult the 74LVC245 datashett for more details, but essentially: connect VCC to your logical level that you want to convert (for example, 3.3V), the Ground connects to Ground. Wire OE (output enable) to earth to activate the device and DIR (direction) to VCC. Then, the digital logic on pins A up to 5V will appear on pins B shifted to the VCC logic.