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ljbeng
Joined: 10 Feb 2004
Posts: 205
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| Analog Conversion 18F4620 |
 Posted: Fri May 02, 2008 8:29 am |
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I have never had problems with analog conversion before. This is a fairly new board, good ground plane, 4.96vdc regulation. I am using 3 analog inputs. One is a temp sensor (0-5v out), one channel is a 10k pot and the 3rd channel is grounded for now. I keep getting full scale output on a channel that only has .75 volts on it. At the same time, the other channels increase in value, even the grounded input gives me a reading of 7-9. I have tried new chips but they all do the same. Here is the program. Thanks for looking. Compiler is 3.249.
| Code: |
#include <18f4620.h>
#device ICD=TRUE
#device adc=10
#FUSES WDT //Watch Dog Timer
#FUSES WDT128 //Watch Dog Timer uses 1:128 Postscale
#FUSES HS //High speed Osc (> 4mhz)
#FUSES NOPROTECT //Code not protected from reading
#FUSES NOIESO //Internal External Switch Over mode disabled
#FUSES NOBROWNOUT //No brownout reset
#FUSES BORV21 //Brownout reset at 2.1V
#FUSES NOPUT //No Power Up Timer
#FUSES NOCPD //No EE protection
#FUSES STVREN //Stack full/underflow will cause reset
#FUSES NODEBUG //No Debug mode for ICD
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOWRT //Program memory not write protected
#FUSES NOWRTD //Data EEPROM not write protected
#FUSES NOEBTR //Memory not protected from table reads
#FUSES NOCPB //No Boot Block code protection
#FUSES NOEBTRB //Boot block not protected from table reads
#FUSES NOWRTC //configuration not registers write protected
#FUSES NOWRTB //Boot block not write protected
#FUSES FCMEN //Fail-safe clock monitor enabled
#FUSES NOXINST //Extended set extension and Indexed Addressing mode disabled (Legacy mode)
#FUSES NOPBADEN //PORTB pins are configured as analog input channels on RESET
#FUSES LPT1OSC //Timer1 configured for low-power operation
#FUSES MCLR //Master Clear pin enabled
#use delay(clock=20000000,RESTART_WDT)
//#include <bootloader.h>
#include <math.h>
#include <stdlib.h>
#use fast_io(a)
#use fast_io(b)
#use fast_io(c)
#use fast_io(d)
#use fast_io(e)
#zero_ram
#use rs232(baud=9600,parity=N,xmit=pin_c6,rcv=pin_c7,bits=8,ERRORS)
int16 tempf,windt,windcnt,windir,raincnt,stotal,auxcnt,auxanalog;
#int_TIMER1
TIMER1_isr(){
set_timer1(15536);//.01 sec interrupts
windt++;
}
#int_EXT
EXT_isr(){
windcnt++;
}
#int_EXT1
EXT1_isr(){
raincnt++;
}
#int_EXT2
EXT2_isr(){
auxcnt++;
}
void main(){
//********** INITIALIZE CHIP **********
set_tris_a(0b00010111);
set_tris_b(0b00110111);
set_tris_c(0b10001100);
set_tris_d(0b11000000);
set_tris_e(0b00000000);
setup_adc_ports(AN0_TO_AN2|VSS_VDD);
setup_adc(ADC_CLOCK_DIV_16|ADC_TAD_MUL_8);
//I have tried many settings above and am now guessing what the settings should be...
setup_wdt(WDT_ON);
setup_timer_0(RTCC_INTERNAL);
setup_timer_1(T1_INTERNAL|T1_DIV_BY_1);
setup_timer_2(T2_DISABLED,0,1);
setup_timer_3(T3_INTERNAL|T3_DIV_BY_1);
enable_interrupts(INT_TIMER1);
enable_interrupts(INT_EXT);
enable_interrupts(INT_EXT1);
enable_interrupts(INT_EXT2);
enable_interrupts(GLOBAL);
while(1){
restart_wdt();
if (windt >= 300){
set_adc_channel(0);
delay_us(10);
windir = read_adc();
set_adc_channel(1);
delay_us(10);
tempf = read_adc();
set_adc_channel(2);
delay_us(10);
auxanalog = read_adc();
disable_interrupts(GLOBAL);
stotal = tempf + windcnt + windt + windir + raincnt + auxanalog + auxcnt;
//printf("$WTH,%04lu,%04lu,%04lu,%04lu,%04lu,%04lu,%04lu,%04lu\r\n",tempf,windcnt,windt,windir,raincnt,auxcnt,auxanalog,stotal);
printf("$WTH,%04lu,%04lu,%04lu\r\n",tempf,windir,auxanalog);//analog only
enable_interrupts(GLOBAL);
windt = 0;
windcnt = 0;
raincnt = 0;
auxcnt = 0;
}
}
}
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Output of serial port:
| Code: |
$WTH,0158,0013,0471
$WTH,0157,0002,0472
$WTH,0157,0000,0472
$WTH,0157,0000,0471
$WTH,1023,0016,0539
$WTH,1023,0008,0541
$WTH,1023,0009,0539
$WTH,0157,0000,0471
$WTH,0157,0000,0472
$WTH,0157,0000,0472
$WTH,1023,0011,0540
$WTH,1023,0010,0539
$WTH,1023,0009,0541
$WTH,0157,0000,0470
$WTH,0158,0000,0473
$WTH,0157,0004,0471
$WTH,0157,0000,0471
$WTH,1023,0010,0540
$WTH,1023,0008,0540
$WTH,1023,0010,0540
$WTH,0158,0000,0471
$WTH,0158,0000,0472
$WTH,0157,0000,0471
$WTH,1023,0009,0540
$WTH,1023,0009,0539
$WTH,1023,0010,0539
$WTH,0157,0000,0472 |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri May 02, 2008 11:05 am |
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I would make a test program that simply reads and displays the 3 A/D
channels in a while() loop, with a short delay (1/2 sec) for the loop.
I would get rid of all the fast i/o and tris statements, also get rid of all
interrupts and timer statements. Disable the Watchdog timer. Make
the printf statement much more simple. Just use "%lu" for the format
string. Don't do any math on the results. Get rid of the ICD=TRUE
and run it as a standalone program. |
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ljbeng
Joined: 10 Feb 2004
Posts: 205
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| Posted: Fri May 02, 2008 1:33 pm |
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I did all you said, made it a very basic program with 1s delay between serial xmit. It does this now, at least it's a pattern....
| Code: |
$WTH,157,278,603
$WTH,156,274,606
$WTH,157,276,525
$WTH,159,279,486
$WTH,157,274,565
$WTH,155,279,599
$WTH,156,276,564
$WTH,157,278,492
$WTH,1023,343,1023
$WTH,1023,346,1023
$WTH,1023,344,1023
$WTH,1023,347,1023
$WTH,1023,343,1023
$WTH,1023,325,1023
$WTH,157,275,620
$WTH,159,277,514
$WTH,156,282,504
$WTH,157,278,578
$WTH,157,280,606
$WTH,158,277,540
$WTH,159,274,492
$WTH,1023,343,1023
$WTH,1023,343,1023
$WTH,1023,343,1023
$WTH,1023,344,1023
$WTH,1023,347,1023
$WTH,1023,343,1023
$WTH,1023,343,1023
$WTH,157,275,563
$WTH,159,272,501
$WTH,157,278,513
$WTH,157,277,587
$WTH,157,274,614
$WTH,157,274,536
$WTH,162,274,493
$WTH,1023,347,1023
$WTH,1023,343,1023
$WTH,1023,342,1023
$WTH,1023,348,1023
$WTH,1023,349,1023
$WTH,1023,342,1023
$WTH,1023,344,1023
$WTH,158,274,536
$WTH,159,269,489
$WTH,157,278,536
$WTH,157,273,599
$WTH,157,273,591
$WTH,157,276,516
$WTH,158,280,485
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri May 02, 2008 1:53 pm |
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| Post the program. |
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