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Workbench Wednesdays

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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.

In August 2022, Nordic Semiconductor announced its first Wi-Fi product. The nRF7002 is a dual-band (2.4 and 5 GHz) Wi-Fi 6 compatible companion IC. It does not have a general-purpose microcontroller built-in. Instead, Nordic intends for you to combine it with another microcontroller, like one of their nRF52 or nRF53-series system on chip (SoC).

During the component shortage, I got to know Raspberry Pi’s RP2040 microcontroller. It is a dual-core Arm Cortex-M0+ with about 262 kilobytes of RAM. The feature I like most is the programmable IO pins. These are small state machines that run independently of the Arm cores. They allow for some clever tricks. For example, I used them extensively on the Mega IIe project.