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freesat
Joined: 08 Feb 2011
Posts: 32
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| Problem with output_float ? |
 Posted: Mon May 12, 2014 10:32 pm |
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Hi, i have problem passing PIN as function parameter and output_float, see sample codes below.
| Code: |
// this one works fine, with fixed const PIN
using: x = onewire_read();
int onewire_read() {
int count, data;
for (count=0; count<8; ++count) {
output_low( PIN_B0 );
delay_us( 2 );
output_float( PIN_B0 );
delay_us( 8 );
shift_right(&data,1,input( PIN_B0 ));
delay_us( 120 );
}
return( data );
}
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| Code: |
// This works!!! ouput_float is not accepting PIN_B0 passed on parameter
using: x = onewire_read( PIN_B0 );
int onewire_read( int16 one_wire_pin ) {
int count, data;
for (count=0; count<8; ++count) {
output_low( one_wire_pin );
delay_us( 2 );
output_float( PIN_B0 ); // SEE THIS LINE
delay_us( 8 );
shift_right(&data,1,input( one_wire_pin ));
delay_us( 120 );
}
return( data );
}
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| Code: |
// This wont works!
using: x = onewire_read( PIN_B0 );
int onewire_read( int16 one_wire_pin ) {
int count, data;
for (count=0; count<8; ++count) {
output_low( one_wire_pin );
delay_us( 2 );
output_float( one_wire_pin );
delay_us( 8 );
shift_right(&data,1,input( one_wire_pin ));
delay_us( 120 );
}
return( data );
}
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so there is a problem with output_float? or im doing something wrong?
PS. Tested with version 5.025 and real hardware ( DS18B20 ) |
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stinky
Joined: 05 Mar 2012
Posts: 99
Location: Central Illinois
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| Posted: Mon May 12, 2014 10:47 pm |
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| I believe you'll need to use a pointer to solve this. |
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temtronic
Joined: 01 Jul 2010
Posts: 9241
Location: Greensville,Ontario
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| Posted: Tue May 13, 2014 6:54 am |
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also.... from the help files..
"Note that doing I/0 with a variable instead of a constant will take much longer time."
so I wonder if that's your problem...a timing issue or does it just 'fail'.
depending on application, it might be easier,quicker, smaller code to create 'fixed' code functions instead of variables?
also... as this code accesses an RTC why the 'variable' pin requirement ? There's a working driver in the code library. Normally you only have one RTC per PIC.
curious
jay |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Tue May 13, 2014 8:28 am |
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what does the .LST file show after you compile for that region of code ??
does the pin number ( from the device.H file) show up as expected ? |
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freesat
Joined: 08 Feb 2011
Posts: 32
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| Posted: Tue May 13, 2014 3:30 pm |
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| Quote: |
hi stinkyi, thanks for reply, i try pass parameter as pointer, does not help!
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| Quote: |
Hi Temtronic, thanks for reply, is not just time delay issue, it fail completly, u can wait forever, and it never does expedtec.
I need variable code to read 4 ( 1wire lines on same pic ), so create same code four times to do the same, sound no good.
( it is for DS18B20 temperature sensors, read a lot of sensors, so need more than one pin with more than one sensor on each pin, not RTC, i prefer ds3231/i2c as RTC. )
something like this....
read_onewire( PIN_B0, SensorID1 )
.....
read_onewire( PIN_B0, SensorID5 )
read_onewire( PIN_B1, SensorID1 )
.....
read_onewire( PIN_B1, SensorID5 )
read_onewire( PIN_B2, SensorID1 )
.....
read_onewire( PIN_B2, SensorID5 )
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| Quote: |
Hi asmboy, thanks for reply, see below for .lst produced by compiler
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| Code: |
.................... output_float( PIN_B0 ); // Using const
045D: BSF 03.5
045E: BSF 06.0
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| Code: |
.................... output_float( one_wire_pin ); // Using variable parameter
045D: MOVF 44,W
045E: MOVWF 48
045F: MOVLW 01
0460: MOVWF 49
0461: CLRF 4B
0462: MOVLW 80
0463: MOVWF 4A
0464: CALL 397
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[/quote] |
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asmboy
Joined: 20 Nov 2007
Posts: 2128
Location: albany ny
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| Posted: Tue May 13, 2014 3:47 pm |
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ok the problem is clear to me .
RTM !! 
quoting what is expected by the compiler - of the argument supplied to
output_float(PIN);
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Requires: Pin constants are defined in the devices .h file
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the compiler SHOULD have error-ed when you spec'd a VAR instead of a constant, but instead went spinning off the rails as .LST shows.
IS there any more to be learned from the CALL at 397 ?? - as you did not show what was there .
SO....
as-is the function expects a CONSTANT, which it encodes at compile time-
and in runtime - as per the Urban dictionary -you are SOOL
there is of course a way to deal with what you want to do - but not using a VAR.
Last edited by asmboy on Tue May 13, 2014 5:13 pm; edited 1 time in total |
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temtronic
Joined: 01 Jul 2010
Posts: 9241
Location: Greensville,Ontario
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| Posted: Tue May 13, 2014 5:04 pm |
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oops...been a long week, already burned out...OK...not RTC but temp sensor...
If they all have IDs, you can run an 'interrogation' function, get their ids, then use that 'database' to access them as required.
In my case( 2 sensors, solar wall project), using a second I/O pin was easier to code,simpler to wire and a bit more reliable. The ones I used were the PS type( parasitic mode) so 2 wires per sensor( I/O pin and ground).
I also tend to use 40 pin PICs for every project.I know 'overkill' but seem to always need 'just one more pin....'
Just another way to use them.....
hth
jay |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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