Bus Pirate: Reclaiming the Vpullup pin

The Bus Pirate Vpullup pin supplies a voltage to the on-board pull-up resistors. In the “Ultra” hardware it also powers the external half of the bi-directional IO buffer. MOSI CLOCK MISO CS AUX AUX2 (formerly ADC) Vpullup AUX4 (formerly 3.3Volts) 0.8-5.0Vout (formerly 5.0Volts) GND So far we’ve added voltage measurement to every IO pin and […]

Bus Pirate: 2K pull-up resistor mod

The Bus Pirate v2go shipped with 10K ohm pull-up resistors (R20-23). We modded our Bus Pirate with a 2K pull-up resistor so we don’t need an external resistor to work with 1-Wire devices. Pull-up resistors larger than 2.2K ohms don’t provide enough current for parasitically powered 1-Wire parts. Since we only need the bigger resistor […]

Bus Pirate: Practical guide to pull-up resistors

See the latest version in the documentation wiki. There’s often some confusion about how the Bus Pirate’s on-board pull-up resistors work. It doesn’t help that the implementation changes drastically from one hardware revision to the next, a lot of the original device tutorials are difficult to follow if you have a Bus Pirate v2go. The […]