Pbasic Syntax

Roger Pierson

Hello,

I was wondering what the difference between these two statements is:

TM PIN 12

and

TM CON 12

Both appear to do the same thing, allow pin 12 to be referenced by TM. I assume there is an advantage to using one method over the other, would somebody be kind enough to show me to the light?

Thanks,

Roger

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Roger Pierson
Senior Electronics Technicain
DTI Assoicates

Mike Green

The difference is that defining TM with a PIN declaration allows you do write "IF TM <> 1" or "TM = 0". The compiler automatically translates the first into "IF IN12 <> 1" and the second into "OUT12 = 0". Read the Basic Stamp Manual, revision 2.2 for a discussion.

allanlane5

Also, the "PIN" declaration only works on version 2.5 of the compiler. The "CON" version works on the earlier version, BUT you must declare the pin INPUT or OUTPUT, and even then, you might need an IN1 declaration to actually 'read' the state of the pin. the "PIN" declaration takes care of that sort of thing for you.

Franklin

The first sets TM to pin 12 and the second sets TM to 12

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- Stephen

Tracy Allen

When PBASC 2.5 first came out there was confusion about that difference. I have a little writeup here, emesys.com/BS2pbasic25.htm#PIN_examples, that goes into more examples. There may be rare cases where you want CON or VAR instead of PIN.

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Tracy Allen
www.emesystems.com

Roger Pierson

Thanks for the info, folks. I was thinking it had something to do with the amount variable space each command took up or something along those lines. Thanks for straightening me out!

Tracy, that was a fantastic article. Thanks!

Roger

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Roger Pierson
Senior Electronics Technicain
DTI Assoicates