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FFT
Joined: 07 Jul 2010
Posts: 92
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| FAST_IO / STANDARD_IO |
 Posted: Tue Jul 13, 2010 3:29 pm |
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Hello,
Before I've been using #use fast_io(D) because all pins were fixed. But now I connected to the PIN_D3 a one-wire sensor and of course this pin must be both input and output. But the other pins are fixed. 1 input and the others are outputs. If I use again #use fast_io(D), the sensor does not work, because the pin is fixed input or output.
Now, How can I force the CCS to generate optimal assembly code for the fixed pins and STANDARD_IO code for the bidirectional (one wire) pin? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Jul 13, 2010 5:26 pm |
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You can put #use standard_io and #use fast_io anywhere in your
program, as much as you want, to control the behavior of the
compiler for code that occurs after that line. Example:
| Code: |
#include <16F877.H>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock=4000000)
#define ONE_WIRE_PIN PIN_D0
#use standard_io(D) // Use standard i/o for the 1-wire driver
#include "1wire.c"
#use fast_io(D) // Use fast i/o for the rest of the program
//==========================================
void main()
{
set_tris_d(0x01); // Pin D0 stays as input
output_high(PIN_D1); // This will use Fast i/o
onewire_reset(); // This will use Standard i/o
output_low(PIN_D1); // This will use Fast i/o
while(1);
} |
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FFT
Joined: 07 Jul 2010
Posts: 92
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| Posted: Wed Jul 14, 2010 6:04 am |
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Wow, I didn't know that, thank you so much  |
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bkamen
Joined: 07 Jan 2004
Posts: 1615
Location: Central Illinois, USA
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| Posted: Wed Jul 14, 2010 1:19 pm |
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You can also set up control over the IO Direction control registers (TRIS) and change in Input/Output config as you need.
When I need mostly fast_io, I usually do that.
Either way works.
-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D |
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