9 Replies Latest reply on Dec 19, 2016 7:38 AM by userc_39282

    PSoC 5LP - Signal Generator

      I am making a signal generator for a school summative project, due in January, but I need it done by the 21st of December as I will be away with family on vacation for 3 weeks.


      My plan for this is to have a menu system on a 16x4 HD44780 display, and digital control of external wave-dacs to generate either a sine wave, triangle wave, sawtooth wave, ramp wave, or possibly a custom waveform from an external storage device. There will also be a separate terminal for the square wave that has variables tied to the other waves, but also will have a duty cycle, and pulse setting.


      In the menu you will be able to change the frequency, amplitude, voltage offset, duty cycle, table steps, pulse, and be able to reset the settings to default. It will save values on power down. Also in the menu, you can change how much you change values by, in powers of 10: 1, 10, 100, 1K, 10K, 100K, and 1M. There will also be a power on/off switch, and it will likely be a soft power-on button of sorts.


      On screen, it will always display the current settings position at the bottom of the display, and will always display frequency as F###, amplitude as A###, offset as V+-#.#, and table step as TS###. Frequency and amplitude will have either nothing, a K, or an M depending on if it is 1000 or above, or 1000000 or above.


      The table will have maximum either 256 or 512 steps to still attain a high enough frequency, and I will likely be using a 10mhz wave-dac, as the internal wave-dacs can only reach 1Mhz and no more.


      If you have any suggestions, feel free to say. I will try to keep this thread updated as much as I can, whenever I do something on this project.




      Dec 12 EDIT:


      So the project took some turns away from the original project guidelines I set, but it is ready for operation through two 0.5V from rail opamps (quite a pretty penny for them).


      It has it's own case from an old machine that fits it perfectly, and it's powered by a $300 +5V, +24V, +-12V power supply that was lying around for a few years. The unit will have about 8 or 9 BNC jacks on the from panel and can adjust the amplitude of the wave terminals along with the frequency, wave type, and voltage offset. It can also switch the output mode of it's power supply from constant voltage to constant current with a variable feedback resistor on the regulators.


      It seems to have gotten very complex, but my dad is an excellent teacher who knows all there is to know for a near expert about electrical components. He built the power supply circuitry without me, but explained it in detail, and did it alone to make it up to CSA standards. The first thing to go is a 2 amp primary input fuse in an inline screw package in the back of the case if anything were to go wrong. It has two low speed fans and a filter, and the PSoC is isolated from the PSU. It also has electrical isolation between the power supply outputs.


      All around it looks nice, and will likely be a good instrument in the lab, and will likely fetch a nice score for my final project.


      Off topic a bit, the unit has character with a brushed aluminium finish, and stained copper coated aluminium interior, visible through the fans. The front will be a raw wood panel, and will likely be finished over and polished to look nice. I will post a picture when it is complete.




      Dec 19 EDIT:


      Here is the link to the project page on hackster.io https://www.hackster.io/sam-chamberlain/psoc-5lp-function-generator-school-project-f05047