Electronics > Beginners
555 or Op-amp?
MarkF:
If you would like something more advanced, take a look at a function generator I did with a PIC18F2550 microcontroller, AD9834 DDS chip and a MCP4812 Dual 10-Bit DAC. 1Hz to 10MHz at 5Vpp. Output sine, triangle, square, sine sweep, triangle sweep and PWM waveforms. (Still working on PWM waveform. I may not be able to get the code to fit in the PIC.)
Kilroywashere:
--- Quote from: MarkF on March 18, 2019, 09:55:59 pm ---If you would like something more advanced, take a look at a function generator I did with a PIC18F2550 microcontroller, AD9834 DDS chip and a MCP4812 Dual 10-Bit DAC. 1Hz to 10MHz. Output sine, triangle, square, sine sweep, triangle sweep and PWM waveforms. (Still working on PWM waveform. I may not be able to get the code to fit in the PIC.)
--- End quote ---
I have seen a few with atmegs 328 and i seen one with an atmega16 I was kinna hoping to do this analog style .... DDS its called right?
http://www.electronics-lab.com/project/dds-function-generator/
This is the one i saw it looked very nice !
If i was going to add an atmega328 i would only like to use it for a LCD display
Pic is still out of my capability ... i have a k150 and i have never been able to get it to work....
I tought since i have alot of 555's and a few op-amps i would go analog ...
If you have seen any designs that good let me know ....
Yours looks very neat tho....im have never messed around with a DAC before i dont think Thats a digital to analog converter right?
So I guess you get the wave from the pic and the DAC changes it to an analog signal and feeds it to the op amps... and the op-amp amplifies the signal?
https://hackaday.com/2018/03/02/tiny-function-generator-on-the-attiny85-complete-with-oled/ this one uses a attiny85 ... thats cool
MarkF:
--- Quote from: Kilroywashere on March 18, 2019, 10:08:50 pm ---
--- Quote from: MarkF on March 18, 2019, 09:55:59 pm ---If you would like something more advanced, take a look at a function generator I did with a PIC18F2550 microcontroller, AD9834 DDS chip and a MCP4812 Dual 10-Bit DAC. 1Hz to 10MHz. Output sine, triangle, square, sine sweep, triangle sweep and PWM waveforms. (Still working on PWM waveform. I may not be able to get the code to fit in the PIC.)
--- End quote ---
I have seen a few with atmegs 328 and i seen one with an atmega16 I was kinna hoping to do this analog style .... DDS its called right?
http://www.electronics-lab.com/project/dds-function-generator/
This is the one i saw it looked very nice !
If i was going to add an atmega328 i would only like to use it for a LCD display
Pic is still out of my capability ... i have a k150 and i have never been able to get it to work....
I tought since i have alot of 555's and a few op-amps i would go analog ...
If you have seen any designs that good let me know ....
Yours looks very neat tho....im have never messed around with a DAC before i dont think Thats a digital to analog converter right?
So I guess you get the wave from the pic and the DAC changes it to an analog signal and feeds it to the op amps... and the op-amp amplifies the signal?
--- End quote ---
A DAC is a digital-to-analog converter as you say. It performs the same function as the R2R resistor ladder network that feeds the op-amps in the circuit you linked to.
The MCP9812 has two DACs and is controlled via a SPI interface. The DACs in my design control the amplitude and DC offset of the analog output.
The AD9834 generates the sine, triangle and square wave set by the PIC.
The PIC also generates the frequency sweep, sweep start trigger and PWM outputs (at TTL levels).
There is no reason my design could not use an Arduino instead of the PIC.
Here is a picture of my prototype.
MarkF:
The ATTiny example is very flexible in the number of waveforms it generates. Essentially, an arbitrary waveform generator. I did it with a PIC16F877A some time ago. However, it is very limited in the frequency that it can generate. I seem to remember that I was only able to generate a maximum frequency of 15KHz with the PIC's max clock freq of 8MHz.
Kilroywashere:
--- Quote from: MarkF on March 18, 2019, 09:55:59 pm ---If you would like something more advanced, take a look at a function generator I did with a PIC18F2550 microcontroller, AD9834 DDS chip and a MCP4812 Dual 10-Bit DAC. 1Hz to 10MHz at 5Vpp. Output sine, triangle, square, sine sweep, triangle sweep and PWM waveforms. (Still working on PWM waveform. I may not be able to get the code to fit in the PIC.)
--- End quote ---
Is the 10 or 12 bit DAC on the attiny85 Good enough for your design, could i use that in place of the MCP4812 ?? and can i use a 16x2 lcd screen ?
I could use the atmega328p in place of the pic ....
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version