Category: Function Generator

DDS Function generator

This has been on my list of things to do for a while and represent a few challenges. Chips like AD9851 contains a full DDS that interface to a MCU on one side and give 3.3V signals on the other side. I have yet to decide wherever  to use AD9851 or something else, butAD9851 is…

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BasicPI Firmware Stack

This illustrates the BasicPI Firmware Stack in progress. What I always do in embedded applications is to make a “standard” main.cpp as follows: void AppInit() {    // wire hardware } int main() {    AppInit();    // start OS } A team I worked in years ago agreed on this standard so we should…

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Programmable DDS – Part 2

  This illustrate the main functionality I want to achieve. The DDS can generate waveforms as well as more classic squares, triangles, sinus etc. I would like a signal that can be amplified to +/-20V and given a base offset anywhere within that range. The blue line illustrate a more classic square signal starting at…

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AD5231 Digital Potentiometer

I showed the MOSFET driven resistor array earlier and while searching for digital potentiometers I found 2 that are SPI based on 10K. One is the MCP41010 with 255 steps, but the one I really liked is the new AD5231 with 1024 steps. They exist in 10K, 50K and 100K versions and provide a far…

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Analogue, Programmable PSU

This weird circuit is a programmable, analogue PSU. It is basically only a LM317 and an array with resistors and MOSFET’s so I can program the voltage out by selecting a combination of 10 resistors. This is not straight forward, but I can at least Select 10 preset values. In addition I use an ADC…

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Function Generator Hat

I need a function generator and I like AD9851. What I really would like is a Function Generator Hat with programmable +/- voltage like the diagram below: This is not impossible, but the DDS, Amplifier and Programmable PSU on a small Hat is not realistic. Or – well – I need to think about that…

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