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sirmeowsalot
Joined: 18 Jan 2013
Posts: 7
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| Variable for value in setup_vref not working |
 Posted: Fri Jan 18, 2013 5:56 pm |
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So I want to vary the value of vref in the project I'm working on, but I'm finding that something like:
| Code: | int vtest = 10;
setup_vref(VREF_OUT_CVREF | VREF_C1_HIGH | vtest);
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won't work at all, but this:
| Code: | setup_vref(VREF_OUT_CVREF | VREF_C1_HIGH | 10);
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works just fine.
Any ideas on why or how I can get it to work?
edit:
ICD3
PIC16F785
MPLAB X |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Jan 18, 2013 9:45 pm |
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What is your CCS compiler version ? This problem is likely dependent
upon the version.
The version is a 4-digit number given at the top of the .LST file.
The .LST file is generated after a successful compilation and will be
in your project directory. Examples of version numbers:
http://www.ccsinfo.com/devices.php?page=versioninfo |
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sirmeowsalot
Joined: 18 Jan 2013
Posts: 7
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| Posted: Mon Jan 21, 2013 12:12 pm |
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Thanks for the response, PCM programmer!
Looks like we're running 4.130
Should I see if I can get them to update/upgrade? Can anyone verify that it works with a newer version of the compiler? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Jan 21, 2013 1:22 pm |
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If someone else doesn't check if the version makes a difference in the
generated code, I do it in about 6 hours from now. I can't do it at my
present location. |
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sirmeowsalot
Joined: 18 Jan 2013
Posts: 7
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| Posted: Mon Jan 21, 2013 6:20 pm |
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| Awesome! Thanks in advance! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Jan 21, 2013 8:25 pm |
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There is a bug in vs. 4.130 for setup_vref() for the 16F785. The code
doesn't load the REFCON register correctly. The bug still exists in vs. 4.140.
| Code: |
0017: MOVLW 0A // 10 -> Wreg
0018: BCF 03.6
0019: MOVWF 25 // Wreg -> vtest
.................... int vtest = 10;
....................
.................... setup_vref(VREF_OUT_CVREF | VREF_C1_HIGH | vtest);
001A: MOVF 25,W // main.vtest -> Wreg
001B: IORLW 80 // OR Wreg with VREF_C1_HIGH (0x80)
001C: MOVWF 26 // Wreg -> main.@SCRATCH1
001D: MOVLW 02 // VREF_OUT_CVREF (02) -> Wreg
001E: MOVWF 27 // Wreg -> main.@SCRATCH2
001F: MOVF 26,W // main.@SCRATCH1 -> Wreg
0020: BSF 03.5
0021: MOVWF 19 // Wreg -> VRCON
0022: MOVF 00,W // INDF -> Wreg *** Bug - should load from @SCRATCH2
0023: MOVWF 18 // Wreg -> REFCON
....................
.................... setup_vref(VREF_OUT_CVREF | VREF_C1_HIGH | 10);
0024: MOVLW 8A
0025: MOVWF 19 // VRCON = 0x8A
0026: MOVLW 02
0027: MOVWF 18 // REFCON = 0x02
.................... |
Here is a macro that will replace the built-in setup_vref() function.
Place the macro code above main(), as shown below, and then
call setup_vref().
| Code: |
#include<16F785.h>
#fuses INTRC_IO,NOWDT
#use delay(clock = 4M)
#byte VRCON = getenv("SFR:VRCON")
#byte REFCON = getenv("SFR:REFCON")
int16 temp16;
#define setup_vref(value) \
temp16 = value; \
VRCON = temp16; \
REFCON = temp16 >> 8
//=============================
void main()
{
int vtest = 10;
setup_vref(VREF_OUT_CVREF | VREF_C1_HIGH | vtest);
while(1);
}
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sirmeowsalot
Joined: 18 Jan 2013
Posts: 7
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| Posted: Tue Jan 22, 2013 1:45 pm |
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Awesome! You rock, PCM programmer!
Thanks for the macro!
Not very good at assembly so I couldn't figure out what it was doing differently when I took a look earlier, so thanks for the explanation on that as well! |
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bkamen
Joined: 07 Jan 2004
Posts: 1611
Location: Central Illinois, USA
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| Posted: Tue Jan 22, 2013 5:57 pm |
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This is why it's a good thing to learn assembler - for future reference.
Little things like this will become easy to find and easy to fix.
I recently ran into a similar problem with setup_vref on the PIC24 series with PCD.
setup_vref was writing to the wrong register.
-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D |
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