The I2C bus level shifting feature allows the user to join 5 volt I2C buses and 1.8-6 volt I2C buses. E.g., it can be used as an adapter, when Tracii 400, which is designed to be connected to 5 volt I2C buses only, should be used to trace the traffic on 1.8-6 volt I2C buses. Check the 'Low-voltage I2C Bus with Tracii 400 and Audrii' article on the FAQ page for details.

Audrii has several I2C Devices onboard:

I/O-Expander

The I/O-Expander PCF8574 is soldered on the board. It can be completely disabled and its address can be configured using jumpers.

6 I/O-lines are connected to on-board LEDs. 2 I/O lines are connected to switches. All 8 signal lines are also available at the prototyping area.

Memory

One socket on the board is dedicated to hold a memory device. One PCF8570 RAM device, which can be plugged into that socket is shipped with the board. It is possible to replace that device by a pin- compatible I2C memory device such as a 24LC0x EEPROM.

The memory device's address can be configured by jumpers

In case a simple I2C master is required in an application, a PIC16C71 microcontroller can be plugged into a dedicated socket on the board.

Using Audrii, a given 5 volt or a 1.8-6 volt I2C bus can be easily extended by an I/O-expander (PCF8574), a memory device (e.g. RAM PCF8570 or optionally EEPROM 24LC00 and pin-compatibles) and a PIC16C71 microcontroller. Thus, it is possible to complement a given I2C system with slave devices (I/O-expander, memory) or a master device (microcontroller) provided by Audrii.

The I/O-expander's I/O-lines are connected to on-board LEDs and switches. Furthermore, these signal lines as well as the microcontroller's I/O-signals are available at a header at the edge of the prototyping area.

You can connect Audrii via the 4 pin 2.5 mm I2C connector to your I2C bus our our products. A second 4 pin connector is available on the other side of the level shifter. Further I2C connection possibilites are:

• 15 pin SUB-D male connector
• PS/2 connector (Mini-DIN 6 pin female connector)