PIC High Voltage

Hi
At what voltage is a Pic's input pin considered high or on, i.e.
do you have to be higher than say 1 volt. I've looked all over and I
am sure the answers out there but I can't seem to cut through the
mountains of information.

 

[Byron A Jeff]

In article <b5tcg0td7g7lm7584prp255femumi5jvkm@4ax.com>,
<stephen@toppuk.co.uk> wrote:

Hi
At what voltage is a Pic's input pin considered high or on, i.e.
do you have to be higher than say 1 volt. I've looked all over and I
am sure the answers out there but I can't seem to cut through the
mountains of information.

0.8Vdd which is 4 volts if Vcc is te nominal 5V.

Note this is not TTL compatible.

For some more info on the subject you can read the release notes section for
my Trivial PIC programmer: http://www.finitesite.com/d3jsys/index.html#RELEASE

BAJ

 

[Gareth]

stephen@toppuk.co.uk wrote:

Hi
At what voltage is a Pic's input pin considered high or on, i.e.
do you have to be higher than say 1 volt. I've looked all over and I
am sure the answers out there but I can't seem to cut through the
mountains of information.

The answer will be in the datasheet - look for a table called "DC
Characteristics". I would advise you to check the datasheet of the PIC
you are using, but as an example for the PIC16F877 the high input
minimum is:

for TTL buffers: 0.25*Vdd+0.8V
for schmitt buffers: 0.8*Vdd

--
-----------------------------------------------------------------------
To reply to me directly:

Replace privacy.net with: totalise DOT co DOT uk and replace me with
gareth.harris

 

Thanks for the replies.


On Tue, 27 Jul 2004 16:30:22 GMT, stephen@toppuk.co.uk wrote:

Hi
At what voltage is a Pic's input pin considered high or on, i.e.
do you have to be higher than say 1 volt. I've looked all over and I
am sure the answers out there but I can't seem to cut through the
mountains of information.

 

Thanks for the info.

On Tue, 27 Jul 2004 19:46:15 +0100, Gareth <me@privacy.net> wrote:

stephen@toppuk.co.uk wrote:
Hi
At what voltage is a Pic's input pin considered high or on, i.e.
do you have to be higher than say 1 volt. I've looked all over and I
am sure the answers out there but I can't seem to cut through the
mountains of information.

The answer will be in the datasheet - look for a table called "DC
Characteristics". I would advise you to check the datasheet of the PIC
you are using, but as an example for the PIC16F877 the high input
minimum is:

for TTL buffers: 0.25*Vdd+0.8V
for schmitt buffers: 0.8*Vdd