Logic level

Z

zener

Member
Hi all,

I know I have either read this (logic level) in the manual or on a past thread, but I cannot find it again (or remember the answer).

I would like to know what the voltage range is on a Picaxe (28x2) when it will detect a high, and while I'm at it, what a low is?

I had a feeling for a high it was something llike 90% of 5v and a low 10% of 5v.

I know someone here will know the answer.

Thanks
 
D

Dippy

Moderator
Your first point of search should be the Manuals.
Manual 1 Page 8 (online manual).
"Inputs".


For further details you should really check Microchip's PIC Data Sheet.
Electrical Specifications.
First, define which pin. Then you will see if the Input block is TTL or Schmitt Trigger. (2 different types of input stage)
They have slightly different values.
Note. That the Manual plays safe for it's value.


Here is an example from a PIC Data Sheet.
 

Attachments

hippy

hippy

Ex-Staff (retired)
The general rule of thumb I work to for PICmicro is if > 80% of +V it's a high, if < 20% of +V it's a low, and when inbetween consult the datasheet.
 
R

Rbeckett

Member
hippy said:
The general rule of thumb I work to for PICmicro is if > 80% of +V it's a high, if < 20% of +V it's a low, and when inbetween consult the datasheet.
Click to expand...
Naaah, when it is in between hook it to an ADC an call it analog. Hee hee, sorry, couldnt help meself.
Bob
 
D

Dippy

Moderator
Hippy's rule of thumb is based on PIC data and reflects the general spec in the PICAXE Data Sheet which apparently got missed.

If you want nitty-gritty then , as I have said a million times, read the actual PIC data sheet from Microchip. And if you want it bang-on do some measurements for yourself.

Bob, do you want the phone number of my Therapist? :)
 
R

Rbeckett

Member
Thanks for the offer Dippy, but the trip to and from your doc may be a bit of a stretch. Maybe he could just send me drugs and we could call it even? Probably not a good idea. I appologize to Zener for jacking his thread, but he got what he needed, so I played a little..... Sorry, I'll try to behave now.
Bob
 
You must log in or register to reply here.
Top