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cavoti
Joined: 29 Jul 2016
Posts: 11
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| DAC Programming PIC |
 Posted: Fri Jul 29, 2016 2:51 am |
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| Hello I am using a PIC16F1709 and tried to use the DAC. The DAC does something but I have a strange problem. When I write to the DAC the highest value the output is 0.3V and when I write the lowest value the output is 0.9V but my Reference is 3.3V(VDD). I've done all the necessary steps but it still doesn't work. Could someone help me? |
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guy
Joined: 21 Oct 2005
Posts: 297
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| Posted: Fri Jul 29, 2016 4:59 am |
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Please post your code and write your compiler version.
| Quote: | | I've done all the necessary steps but it still doesn't work. |
There must be something wrong or it would work, right? 
Let's keep an open mind when chasing bugs. |
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temtronic
Joined: 01 Jul 2010
Posts: 9226
Location: Greensville,Ontario
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| Posted: Fri Jul 29, 2016 5:20 am |
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as Guy says we NEED to see your code and compiler version.
It could be simple MIScoding or a bug in your version of the compiler. We don't know....until we see your code!
Though I don't use that PIC, most have 'multi use' I/O pins so some other peripheral could still be 'attached' to the DAC pin ?
Jay |
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cavoti
Joined: 29 Jul 2016
Posts: 11
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| Posted: Fri Jul 29, 2016 5:38 am |
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| Code: |
//Mikrokontrollerangabe und Includes
#device PIC16F1709 //Angabe für PIC-Device
#include "16F1709.h" //Standart Bibliothek von PIC16F1709
//Anfangskonfiguration Mikrocontroller
#fuses NOFCMEN, NOIESO, CLKOUT, NOBROWNOUT, NOPROTECT, MCLR, NOPUT, NOWDT, HS //Konfigurationswort 1 konfigurieren
#fuses NOLVP, DEBUG, NOLPBOR, BORV19, NOSTVREN, NOPLLEN, NOZCDDIS, NOPPS1WAY, NOWRT //Konfigurationswort 2 konfigurieren
//Konfigurationen für Gebrauch von zukünftigen Funktionen
#use FAST_IO(C) //Richtungsbestimmung von PORTC-Bits bestimmen
#use delay(clock=16000000,crystal = 16000000) //Clock- und Clocktypangabe
//Konfiguration um uC Register manuell anzusteuern
#byte DAC1CON0 = 0x118 //DAC Konfigurationsregister
#byte DAC = 0x119 //DAC Wertregister
//Definierungen Ports-Bits
#define DAC_Ausgang PIN_A2 //Ausgang Digital-Analog-Wandler
//Initialisierung Globale Variablen
//Variablen für DAC
int8 dac_ausgangswert = 255; //Referenzspannung für Stromregeleschaltung
//DAC Ansteuerung (Hauptprogramm)
void main(void)
{
set_tris_a(0x3B); //PORTA konfigurieren
DAC = 0; //Ausgabewert DAC auf 0 setzen
DAC1CON0 = 0x90; //DAC Konfigurationsregister konfigurieren
delay_ms(10); //Verzögerung 10ms
while(1)
{
DAC = dac_ausgangswert; //Wert ausgeben
}
} |
Last edited by cavoti on Fri Jul 29, 2016 5:41 am; edited 1 time in total |
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cavoti
Joined: 29 Jul 2016
Posts: 11
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| Posted: Fri Jul 29, 2016 5:39 am |
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| sry for answering so late |
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cavoti
Joined: 29 Jul 2016
Posts: 11
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| Posted: Fri Jul 29, 2016 5:42 am |
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| I'm from Switzerland and so I wrote the comments in german |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Jul 29, 2016 9:13 pm |
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You never told us your CCS compiler version. Ttelmah asked you to do
that in the other thread you opened.
The version is given at the top of the .LST file. The .LST file will be in
your project directory after a successful compilation. |
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cavoti
Joined: 29 Jul 2016
Posts: 11
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| Posted: Mon Aug 22, 2016 12:21 am |
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| This is my Compiler Version "CCS PCM C Compiler, Version 5.060" |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19513
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| Posted: Mon Aug 22, 2016 9:09 am |
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Comments:
| Code: |
//Mikrokontrollerangabe und Includes
//#device PIC16F1709 //Angabe für PIC-Device
#include "16F1709.h" //Standart Bibliothek von PIC16F1709
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Loading the processor library automatically defines the processor. You don't need the device line, and having it increases the risk of getting something wrong here.
| Code: |
//Anfangskonfiguration Mikrocontroller
#fuses NOFCMEN, NOIESO, CLKOUT, NOBROWNOUT, NOPROTECT, MCLR, NOPUT, NOWDT, HS //Konfigurationswort 1 konfigurieren
#fuses NOLVP, DEBUG, NOLPBOR, BORV19, NOSTVREN, NOPLLEN, NOZCDDIS, NOPPS1WAY, NOWRT //Konfigurationswort 2 konfigurieren
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Why have you got NOZCDDIS selected?.
This means the ZCD source is permanently enabled on the pin you are using for the DAC output..... You need ZCDDIS.
Also, honestly you want STVREN enabled.
Once you have turned off the ZCD, the remaining question will be the load you are trying to drive?. Remember this is a high impedance output, and requires a buffer. |
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cavoti
Joined: 29 Jul 2016
Posts: 11
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| Posted: Mon Aug 22, 2016 11:38 pm |
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| The ZCD and STVREN are both already disabled. Are you saying that I have enable it both? |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19513
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| Posted: Tue Aug 23, 2016 12:00 am |
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Not quite.
NOZCDDIS _enables_ the ZCD....
ZCDDIS, disables the ZCD. ZCD disable.
You have the ZCD turned on.
NOSTVREN, means do not reset the chip when a stack full occurs. If you use this, then your code will have to check the stack overflow flag, and do some form of error recovery when an overflow occurs. Much easier (and safer), to have STVREN, which then means if something goes wrong and a stack overflow occurs, the chip will reset (Stack overflow reset enable).
Use:
| Code: |
//Anfangskonfiguration Mikrocontroller
#fuses NOFCMEN, NOIESO, CLKOUT, NOBROWNOUT, NOPROTECT, MCLR, NOPUT, NOWDT, HS //Konfigurationswort 1 konfigurieren
#fuses NOLVP, DEBUG, NOLPBOR, BORV19, STVREN, NOPLLEN, ZCDDIS, NOPPS1WAY, NOWRT //Konfigurationswort 2 konfigurieren
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The ZCD being enabled, is almost certainly what is stopping the DAC2 output from working (on the same pin). |
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cavoti
Joined: 29 Jul 2016
Posts: 11
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| Posted: Tue Aug 23, 2016 12:02 am |
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| Thank you very much:) Sry but I taught that NOZCDDIS means that ZCD ist disabled. |
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cavoti
Joined: 29 Jul 2016
Posts: 11
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| Posted: Tue Aug 23, 2016 12:10 am |
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| I tried it but it still doesn't work. It's really strange because I think I did all the configurations in the right way. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19513
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| Posted: Tue Aug 23, 2016 12:30 am |
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| cavoti wrote: | | Thank you very much:) Sry but I taught that NOZCDDIS means that ZCD ist disabled. |
You were taught wrong.
You can check very easily by compiling the code, and looking at what bits are set in the hex file.
The reason for the naming, is it is an inverted bit. '0' enables the ZCD:
| Code: |
bit 7 ZCDDIS: ZCD Disable bit
1 = ZCD disabled. ZCD can be enabled by setting the ZCDSEN bit of ZCDCON
0 = ZCD always enabled
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NOZCDDIS, sets this bit to '0' (ZCD always enabled). ZCDDIS enables the bit (disabling the ZCD).
However if it still doesn't work, then try the obvious simple test. Remove the PIC. Put a resistor of (say) 4K7 on the DAC2 output, up to your supply voltage. Does it go up to the supply rail?. If it doesn't, then the problem is in the circuit the pin is driving....
Last edited by Ttelmah on Tue Aug 23, 2016 2:15 am; edited 1 time in total |
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cavoti
Joined: 29 Jul 2016
Posts: 11
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| Posted: Tue Aug 23, 2016 12:35 am |
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| Thank you again i will try it:) |
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