All articles tagged as:


Using GreenPak Programmable Logic

In my last post I mentioned that the breakout boards I had designed for the the tiny GreenPak chips had arrived, turns out it was just in time as I discovered a need for them very quickly. A friend of mine needed a simple solution that would allow him to detect button presses through the microphone input of a mobile phone - the quick and dirty solution of simply putting a button and a resistor between ground and the microphone input worked in most cases but for some inputs there wasn't enough noise to generate a measurable change in audio level. I proposed using a small tone generator that wou…

Read more »

GreenPak Programmable Matrix

I had a batch of PCBs arrive yesterday which included the boards for my ESP8266 based sensor system so I should be able to do a followup post on that project in the near future. This batch also included my breakout boards for GreenPak 3 mixed signal programmable logic chips. These devices are small (in terms of size and number of cells) programmable logic chips similar to a PAL (Programmable Array Logic) with support for analog signals as well as digital. Each chip has a collection of configurable cells which can be connected together to implement a circuit. There are a range of cell types a…

Read more »

Ohms Law and Resistor Networks

This post describes how I use Python code to apply Ohms Law to a resistor network to help select optimum component values that don't exceed the operating limits of an IC. In order to determine if the idea I had for controlling a LM317 regulator with a digital potentiometer was workable I had to determine that the limits of the MC4261 digipot would not be exceeded. In this case that means no more than 2.5mA flowing through the digipot resistor and a voltage drop across the resistor of no more than 5V (the supply voltage of the chip). This meant applying Ohms law and calculating the voltage and…

Read more »

Design Idea: Software Controlled Regulator

This post describes the design of a software controlled voltage regulator. At this point I am still trying to determine if the design is feasible within the limits of the components I have available. I have been toying around with ideas for small software controlled modules I can use for circuit analysis and testing. As well as the normal measurement modules you would expect (voltage and current sensing for example) there are also some signal injection modules that would be useful. One of these is a software controlled voltage regulator which could be used to simulate a battery discharging or…

Read more »

UART Based Networking for Microcontrollers

This article describes a simple networking system that supports multiple slave devices connected to a single serial port on the host system. The microcontroller side only requires a UART and can be implemented with a minimal amount of code. Background Almost two years ago I designed and built a small multi purpose bench testing tool to help with fault finding my electronics projects. The goal was to make it easier to measure voltages and currents at multiple points in a circuit without a desk full of multimeters. I wound up with a workable unit (workable enough for me to use at least) but the…

Read more »