hello, I was wondering if anyone knows of some chip, or circuit to generate a 500Hz to 10KHz squarve wave. I have used really old VCO(lm331) to do so, but i want to control the frequency digitally, as well as the enable/disable of the signal. this is because every time I enable the system, the wave has to start, with a little delay, but with the VCO, sometimes is in the middle of the pulse, so i have to do a feedback to the processor, and still not very good.
I used a microprocessor (16MHz) to do so, but makes it to be really busy, so I can't do any other process, so I think is a waste.
So if anyone has any idea, will be nice!

Thanks

 

Hi,

I'd use a PSoC microcontroller. You can choose any of their micros, preferably the cheapest and in the package size you want.

You barely need to write any code at all, since the signal would be generated via a digital block. This block does not consume much CPU resources, so you can use the microcontroller to do something else if you want.

Basically, you'd pick a counter block of your desired resolution, up to 32-bits. You can choose from a number of clock sources, Sysclk, Sysclk*2, or three different clocks divided from that. Then, you wire the inside of the IC via a simple graphical interface and select your output type (strong, strong-slow). Then you'd write something like call PWM_Start in the main code, and it's all set. You can modify the period of the clock by writing a single register also.

You can get their development software free along with a really inexpensive USB In-System serial programmer.

Steve

 

You could also have the square wave generated continuously, and use an external gate to pass/block it using an enable signal from the microprocessor.

 

http://www.hightechips.com/HTC555.php

 

Thanks for the information! I will check the chips and see what happen!

For the making the wave continiously, the problem is that I would have to put a feedback to know when the wave start, so I open the gate to let it pass, and that makes the system less flexible! That is why I was thinking a digital way better.

But thanks for the replies