Workbench Wednesdays

Picking I2C Pull-Up Resistors (Correctly)

A long time ago, I made a video suggesting math was unnecessary to determine proper pull-up resistor values. Like most generalized statements, that suggestion is not always true. For example, in data buses like I2C, speeds like 400 kHz and 1 MHz are common. At those speeds, the pull-up resistor and the bus capacitance form an RC filter that fundamentally limits the data transmission speed. Or. It limits the range of pull-up resistor values. In this Workbench Wednesdays video, I show how to estimate I2C bus capacitance, measure that capacitance, and pick pull-up resistor values.

Fan of making things beep, blink and fly. Created AddOhms. Writer for News. Freelance electronics content creator for hire! KN6FGY and, of course, bald.

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