Simple Newbie Question
Simple Newbie Question
Hello all,
······· I have a REALLY dumb question, but I have never had to do this in any of my dealings with programming a Basic Stamp. How, with a Stamp II, do I check to see if a PIN is set to HIGH or LOW. In other words...by default, the PIN should be set to LOW by the stamp...however, the device connected to the PIN may set it to HIGH...how can I tell if this has happened? Any help is GREATLY appreciated.
---
Thomas Cameron
tom@patcameron.ne.mediaone.net
Hello all,
······· I have a REALLY dumb question, but I have never had to do this in any of my dealings with programming a Basic Stamp. How, with a Stamp II, do I check to see if a PIN is set to HIGH or LOW. In other words...by default, the PIN should be set to LOW by the stamp...however, the device connected to the PIN may set it to HIGH...how can I tell if this has happened? Any help is GREATLY appreciated.
---
Thomas Cameron
tom@patcameron.ne.mediaone.net
Comments
Well, by default all pins are inputs. You can set them to outputs using
OUTPUT 1 (for pin 1) and also some commands do this automatically (HIGH 1,
LOW 1, etc.).
You can switch back to input mode with INPUT 1 (again for pin 1).
Now, if the pin is an output, you don't really want to read its state. Why?
Because if an external device has set it to something else, your Stamp and
the device are "fighting". At best you get an unknown state. At worst, you
blow up one or both of the devices.
However, if the pin is an input, try this:
top:
if in1=0 then pin1is0
high 2
goto top
pin1is0:
low 2
goto top
This should make pin2 reflect the state of pin1. You can also read the
inputs in grouups using things like INA (first 4 bits), IND (last 4 bits),
INL (first 8 bits), INH (last 8 bits), etc.
Hope that helps. You might be interested in the Basic Stamp FAQ at
http://www.al-williams.com/wd5gnr/stampfaq.htm.
Regards,
Al Williams
AWC
P.S. You might also enjoy my book "Microcontroller Projects with Basic
Stamps" -- see http://www.al-williams.com/awce/sbook.htm
Original Message
From: Tom Cameron [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=VDqfTm99iAmmh_yfqzuRt6-u9fc68GcYdlKy8xZVxWhfzFIWjNJSr-xXvJGxHf4vq2dJo5_EhqTnVS6gaHcbBCGPVJw]tom@p...[/url
Sent: Friday, September 15, 2000 2:15 AM
To: 'basicstamps@egroups.com'
Subject: [noparse][[/noparse]basicstamps] Simple Newbie Question
Hello all,
I have a REALLY dumb question, but I have never had to do this in
any of my dealings with programming a Basic Stamp. How, with a Stamp II, do
I check to see if a PIN is set to HIGH or LOW. In other words...by default,
the PIN should be set to LOW by the stamp...however, the device connected to
the PIN may set it to HIGH...how can I tell if this has happened? Any help
is GREATLY appreciated.
---
Thomas Cameron
tom@p...