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franckcl
Joined: 12 Sep 2003
Posts: 32
Location: France (Paris)
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| How to change the direction of a I/O ? |
 Posted: Wed Mar 15, 2006 7:59 am |
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Hi all,
In my software, I am using the #USE FAST_IO directive.
Is there a function like "SET_TRIS_X" but for only one bit (and not a Byte) ?
Thank you
Franck |
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Ttelmah
Guest
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| Posted: Wed Mar 15, 2006 8:25 am |
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Not really. The tris register is 'byte wide'. However there are any number of ways of doing this.
1) Have a variable, containing the actual value you want to put into tris. Do a bit set/reset function, and then send the whole variable.
2) Declare the the register yourself using the #byte statement, and then use the #bit statements with this. So:
| Code: |
#define INPUT (1)
#define OUTPUT (0)
#byte TRISA=0xF80
#byte TRISB=0xF81
#byte TRISB=0xF82
#byte TRISC=0xF83
//etc., for as many TRIS registers as you have - change the addresses
//for PIC16/12 chips
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Then either declare a structure for the bits, and map it to these locations (#locate), use the bit I/O functions, or just use bit statements, like:
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#bit TRISA0=TRISA.0
#bit TRISA1=TRISA.1
//etc..
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Then you can just use 'TRISA0=OUTPUT', which makes everything nice and clear!.
Alternatively, with the bit I/O functions, and the 'byte' declarations alone, you can use:
bit_clear(TRISA,0);
or the corresponding 'bit_set' function.
Best Wishes |
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franckcl
Joined: 12 Sep 2003
Posts: 32
Location: France (Paris)
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| Posted: Wed Mar 15, 2006 8:31 am |
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Thank you for your complet respons.
I try this now.
Thank you
Franck |
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