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mmprestine
Joined: 13 Jan 2004
Posts: 29
Location: Green Bay, Wisconsin
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| 12F683 analog |
 Posted: Fri Apr 07, 2006 8:56 am |
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compiler version: 3.242
I have been working on a project that uses the sAN0 and sAN3 analog inputs on the 12F683 and seem to have found serveral discrepencies between the compiled code and the datasheet. Sample code below:
| Code: |
#include <12F683.h>
#device *=8 adc=10
#FUSES NOWDT //No Watch Dog Timer
#FUSES INTRC_IO //Internal RC Osc, no CLKOUT
#FUSES NOCPD //No EE protection
#FUSES NOPROTECT //Code not protected from reading
#FUSES NOMCLR //Master Clear pin used for I/O
#FUSES NOPUT //No Power Up Timer
#FUSES NOBROWNOUT //No brownout reset
#FUSES IESO //Internal External Switch Over mode enabled
#FUSES FCMEN //Fail-safe clock monitor enabled
#use delay(clock=8000000)
#use rs232(baud=4800,xmit=PIN_A1,rcv=PIN_A2,parity=N,bits=8,errors)
//#priority EXT,TIMER0
#ZERO_RAM
void main()
{
setup_oscillator(OSC_8MHZ);
// initialize adc hardware
setup_adc_ports(sAN3|VSS_VDD);
setup_adc(ADC_CLOCK_INTERNAL);
set_adc_channel(sAN3);
while (TRUE){
delay_ms(500);
printf( "Analog Data:%Lu\n\r", read_adc() );
}
}
this results in this ASM:
.................... // initialize adc hardware
.................... setup_adc_ports(sAN3|VSS_VDD);
03F9: BCF 1F.6
03FA: BSF 03.5
03FB: BCF 1F.0
03FC: BCF 1F.1
03FD: BCF 1F.2
03FE: BSF 1F.3
.................... setup_adc(ADC_CLOCK_INTERNAL);
03FF: BSF 1F.4
0400: BSF 1F.5
0401: BCF 1F.6
0402: BCF 03.5
0403: BSF 1F.7
0404: BSF 1F.0
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In the data sheet to setup for sAN3 the control register 1F.2 and 1F.3 should be set. And the select regiester should be 9F and not 1F.
I am I correct about this?
Has any one used the analog on this chip and if so what compiler version?
Regards,
Matt |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Fri Apr 07, 2006 12:20 pm |
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Well, this is an old subject and reason why I even see is between us.
It is an error in the constant definition in the 12F683.h file.
In the paragraph:
// Constants used in SETUP_ADC_PORTS()
Replace this lines
#define sAN0 1 //| GP0
#define sAN1 2 //| GP1
#define sAN2 4 //| GP2
#define sAN3 8 //| GP4
For this:
#define sAN0 0 //| GP0
#define sAN1 4 //| GP1
#define sAN2 8 //| GP2
#define sAN3 12 //| GP4
and the life will smile you.
Humberto |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Apr 07, 2006 12:31 pm |
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Here is an explanation of the listing file:
| Code: |
... setup_adc_ports(sAN3|VSS_VDD);
00D6: BCF 03.5 // Bank 0
00D7: BCF 1F.6 // VCFG = 0
00D8: BSF 03.5 // Bank 1
00D9: BCF 1F.0 // AN0 = digital pin
00DA: BCF 1F.1 // AN1 = digital pin
00DB: BCF 1F.2 // AN2 = digital pin
00DC: BSF 1F.3 // AN3 = Analog pin
... setup_adc(ADC_CLOCK_INTERNAL);
00DD: BSF 1F.4 // ADCS = 011 = use internal clock
00DE: BSF 1F.5
00DF: BCF 1F.6
00E0: BCF 03.5 // Bank 0
00E1: BSF 1F.7 // ADFM = 1 (right justify)
00E2: BSF 1F.0 // ADON = 1
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Also, the parameter you have used in the following line is not valid:
| Quote: | | set_adc_channel(sAN3); |
You must use numbers for the channels. It should be:
| Code: | | set_adc_channel(3); |
This is in the manual. |
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mmprestine
Joined: 13 Jan 2004
Posts: 29
Location: Green Bay, Wisconsin
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| Posted: Fri Apr 07, 2006 1:24 pm |
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Thanks,
I will change it and give it a try. Strange that it compiles with the wrong parameter.
Matt |
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mmprestine
Joined: 13 Jan 2004
Posts: 29
Location: Green Bay, Wisconsin
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| Posted: Fri Apr 07, 2006 1:51 pm |
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| Well as soon as I change the header file to Humberto's new defines and try to use analog 3 the serial does not function anymore. By serial I mean that I am using the external interrupt to parse serial data through a Max232. It appears to be affecting the external interrupt. Any thoughts on this? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Apr 07, 2006 2:01 pm |
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Put the #define statements back to the way they were in
the original 12F683.H file. Example:
| Code: |
#define sAN0 1 //| GP0
#define sAN1 2 //| GP1
#define sAN2 4 //| GP2
#define sAN3 8 //| GP4 |
Then do your A/D setup code like this:
| Code: | setup_adc_ports(sAN3 | VSS_VDD);
setup_adc(ADC_CLOCK_INTERNAL);
set_adc_channel(3); |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Fri Apr 07, 2006 2:28 pm |
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| Quote: |
Put the #define statements back to the way they were in
the original 12F683.H file.
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PCM Programmer you are right, sorry. It was an old issue.
Humberto |
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