Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

First Microcontroller

Status
Not open for further replies.

im_in_asia_now

New Member
I'd like to know which microcontrollers would be best for AC signal generation from DC voltage supply. Also, something that would have a variety of applicatons.

I read about the BASIC Stamp today, and I was impressed by some of its applications. How do the 16F628A or 16F88 (from the newcomer sticky-post) compare to the Stamp?

I'm assuming that since microcontrollers are programmable most of them have the same applications, with limitations being: lines of code, output voltage and current, number of i/o pins. Does that pretty much cover the differences between different microcontrollers?

Also, newbie question so let's go ahead and get it over with. Like I said I'm interested in AC signal generation, not just a square wave from 0 to 5 V, but -5 to 5 V. Is it possible to program a negative output from a pin, which would enable AC signal generation?

Either way, I'd still be interested in trying either a Stamp or one of the other recommended microcontrollers.

Thanks
 
there are people (like me) who have learned to be relatively independent from model No. (number), or I/O pins.

model No. is not that relevant, as for PIC, most code can be ported among them (at least, upwards).

also I/O pins can be expanded, even on 8-pin PICs.

you can generate AC, if you decouple from system ground.
just alternate two pins, first 1/0, then 0/1.
but this is not covering your requirement to generate sinoid waveform.

for this purpose you need external D/A. I do not know maybe you could also feed it in a way that it will produce negative voltage, at least for a few mA.
for larger current you need external negative voltage potential.

simple D/A can be built just from a few resistors, if you do not require high precision. otherwise you'd have to use dedicated D/A IC, which often also can accept external supply voltage.

the D/A IC is then driven by a pattern from a lookup table.
it is not always require to calculate the sinus explicitely directly on the PIC.
 
I read about the BASIC Stamp today, and I was impressed by some of its applications. How do the 16F628A or 16F88 (from the newcomer sticky-post) compare to the Stamp?

The BASIC Stamp is an old PIC built with other components on a small PCB, it's VERY expensive, and VERY slow - because it runs interpreted BASIC.

Either of the two PIC's you mention will massively out perform a Stamp at a fraction of the cost.
 
Thansk everybody for your responses.

From what I saw in BASIC style code you could use basic math functions. Can those math functions be used to control the output? If + - / * can be used to control an output signal, then the Taylor Series representation of a sine wave could be used to simulate a sinusoidal signal between 0 and V(out).

I would prefer a mathematical, code-driven method of signal generation. Is that even possible or do I have to take a completely different approach?
 
There is an old design by Tom Napier which explains how to generate a sine signal using DDS technique with a (horror!) 16F84A. If you manage to understand it you will learn A LOT from there. Google for it.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top