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chungtn
Joined: 25 Jun 2010
Posts: 3
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| Help me! |
 Posted: Fri Jun 25, 2010 9:15 am |
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I use 12f683 but I don't know how to use ADC function, turn off ADC and output signal to ports.
Could you please show me how to use I/O port orientation and repair my program as the following:
| Code: |
#include<12f683.h>
#DEVICE ADC=8
//#define sAN0
#fuses INTRC_IO, NOMCLR,NOWDT,NOPROTECT
#USE delay(internal=8M)
int16 t,a ;
void main(){
set_tris_a(0b00000010)// all pin out except for Pin A1
setup_adc_ports(sAN1);
setup_adc(adc_clock_internal);
while (true) {
set_adc_channel(1);
delay_us(1);
aq==0; //
aq=read_adc();
if (a<1500) //if a<90 then alarm!
{
while(1)
{
output_high(PIN_A3);
delay_ms(30);
output_low(PIN_A3);
delay_ms(30);
}
}
//////////////////////////////////////////////////////
if (a>1500) // neu a>1500
{
t==0;
while(t<100)// loop 100 times
{
t++;
output_high(PIN_A0);//pulse for A0
delay_us(7000); //
output_low(PIN_A0);//
delay_us(7000);
///////////////another chanel/////////////////////////
output_high(PIN_A2);// pulse for A2
delay_us(7000); //
output_low(PIN_A2);//
delay_us(7000);
}
}
}
}
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I have tried to run this progam on demo Proteus and true board circuit. But there is no signal in pin A1 when a<150 and output signal in pin A0 is square is 5V, but signal in pin A0 is square is 2V when a>150.
Could you help me to find the cause of this problem?
Thanks |
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mkuang
Joined: 14 Dec 2007
Posts: 257
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| Posted: Fri Jun 25, 2010 10:53 am |
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There are a few bugs in your code. First you need to know the difference between:
a = 1 and a == 1.
That said, most devices you cannot choose AN1 as the only analog pin while leaving AN0 as digital. Check your device. Usually you have to choose AN0, or AN0 and AN1, or AN0 and AN1 and AN2, so on and so forth. In addition, a delay of 1us is insufficient in most cases to get an accurate A/D reading. Without doing the math I usually use 20us or so and that seems to work. |
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chungtn
Joined: 25 Jun 2010
Posts: 3
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| I don't know why AN0 coressponding to AN1? |
| Posted: Sat Jun 26, 2010 9:17 am |
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| mkuang wrote: | There are a few bugs in your code. First you need to know the difference between:
a = 1 and a == 1.
That said, most devices you cannot choose AN1 as the only analog pin while leaving AN0 as digital. Check your device. Usually you have to choose AN0, or AN0 and AN1, or AN0 and AN1 and AN2, so on and so forth. In addition, a delay of 1us is insufficient in most cases to get an accurate A/D reading. Without doing the math I usually use 20us or so and that seems to work. |
I don't know why AN0 coressponding to AN1? but I repair my progam following your idea and my circuit works right.
Thankyou very much!
Yours sincerely |
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