Mixed voltage interfacing with the Bus Pirate

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This will be an updated guide to using the Bus Pirate pull-up resistors to interface stuff at different voltages.

Contents

About

The Bus Pirate's on-board pull-up resistors can be used to interface electronics above and below the Bus Pirate's 3.3volt supply.

Read how the pull-up resistors on the Bus Pirate work.

Read our guide to pull-up resistors and high impedance pins.

Examples

Here's some examples of how to interface different voltages using the Bus Pirate.

3.3volts

Interface directly with normal pin outputs.

Any voltage 1-Wire, I2C

The Bus Pirate can interface with 1-Wire or I2C at 5.5volts or less.

Open collector buses like 1-Wire and I2C always use pull-up resistors.

If you use the Bus Pirate's on-board pull-up resistors, remember to connect the Vpullup pin to the test circuit supply voltage. The Bus Pirate pull-up resistors are powered through the Vpullup pin.

5.0volts

2.5volts