16f628A - How do I do this?

[Hakachukai]

Hi.

How do I set up a 16F628A to measure the pulse width of a digital signal between 0 and 20khz, and then output the measurement in Hz, or some other useful format? I need it to work in real time, so it must be able to measure them very quickly (around 100 time per second would be nice). Also, I would like to run on the internal oscilator (I want to use the least amount of componets possible)

I'm new to PIC's, but I understand the concept.

I've done x86 assembly, and C programming. Have basic electronics knowlege.

I just dont' know how to use this PIC (I have read some tutorials).

Thanks in advance for your help.

PS. I've Googled for a while now, and haven't found anything that seemed helpful.

 

[bananasiong]

Just learn to use it.
I've been learning PIC since september of last year. I've done a project with PIC. Now I'm still learning, PIC is so powerful.
Go:
http://winpicprog.co.uk
for tutorial. Not only read them but try them

 

[Hakachukai]

Well, I already roughly know how to use it. I've been through some of the tutorials.

What I really need help on is figuring out how to time things. I know that different instructions likely use up different amounts of clock cycles. But these chips are RISC? So does that mean that all instructions use the same amount of clock cycles?

 

[eng1]

So does that mean that all instructions use the same amount of clock cycles?

No, check the Instruction Set Summary in the datasheet.

Also, I would like to run on the internal oscilator (I want to use the least amount of componets possible)

I would suggest to use a crystal, since it's more precise.

BTW are you going to measure the pulse width (high? low?) or the frequency?

 

[blueroomelectronics]

To measure pulse width the CCP hardware will come in handy, see the capture section.

 

[Hakachukai]

In this case I am specifically interested in measuring the frequency.

It doesn't matter to me whether or not I read the rising or falling edge of the pulse, as long as it is always the same each time.

Pardon my ignorance, but what is CCP?

I have to adimt that part of my problem here is not being able to understand the datasheet fully. It's a bit complicated for me sometimes. I'll try to find a capture section in that datasheet.

Thanks for the help so far. I'll keep trying.

 

[mister_e]

CCP: Compare Capture PWM. It's one of those internal module the PIC may provide.

The CCP could be interesting to evaluate the frequency range, once you know the range, you may use an internal Timer/Counter to do the job and set your own sampling time.

An old appnote from microchip...AN592

https://www.electro-tech-online.com/custompdfs/2007/07/00592d.pdf

And CCP tips'n trick
https://www.electro-tech-online.com/custompdfs/2007/07/41214a.pdf