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Message |
paivadaniel
Joined: 11 Mar 2011
Posts: 3
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| AD Converter 18f452 |
 Posted: Fri Mar 11, 2011 10:24 am |
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Hello, I am working with the A / D converter of the PIC 18F452, I'm having trouble capturing a signal of 2.5 V measured by the A / D converter and printed on the screen.
In 18452.h is:
device adc = 8
In X.C file is:
| Code: |
void main ()
{
unsigned int x;
setup_adc_ports (ALL_ANALOG);
setup_adc (ADC_CLOCK_DIV_2);
setup_psp (PSP_DISABLED);
setup_spi (SPI_SS_DISABLED);
setup_wdt (WDT_OFF);
setup_timer_0 (RTCC_INTERNAL);
setup_timer_1 (T1_DISABLED);
setup_timer_2 (T2_DISABLED, 0.1);
setup_timer_3 (T3_DISABLED | T3_DIV_BY_1);
enable_interrupts (INT_RDA);
enable_interrupts (GLOBAL);
/ / parameter not Setup_Oscillator selected from Intr Oscillator Config tab
/ / TODO: USER CODE!
while (1) {
set_adc_channel (7);
delay_us (10);
read_adc x = ();
printf ("\ r% u \ n ", x);
}
}
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My voltage is from 0 to 5V (or FF) should be printing FF / 2 (V = 2.5), but printing is 255 instead of 127. Does anyone know why? I believe that is the problem ADFM. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19535
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| Posted: Fri Mar 11, 2011 10:52 am |
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Several questions/comments:
1) Compiler version -always post this.
2) What clock rate?. FOSC/2, for the ADC clock, is only legal for a maximum of 1.25MHz.....
3) Are you using the RDA interrupt. Have you got a handler for this?. Code will not work properly without this, with the interrupt enabled.
4) Change the SPI setup line, to setup_spi(FALSE). SPI_SS_DISABLED, _enables_ the SPI.....
5) Er. Your read_adc line, is not right as posted. Syntax is:
x=read_adc();
This is probably the main problem.
Best Wishes |
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paivadaniel
Joined: 11 Mar 2011
Posts: 3
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| ops... answer |
| Posted: Fri Mar 11, 2011 11:51 am |
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The code is this, had copied wrong
| Code: |
while (1) {
set_adc_channel (7);
delay_us (10);
read_adc x = ();
printf ("\ r% u \ n ", x);
} |
I use the ccs, PCWHD, new version, the rda is already generated by it.
pq psi should change?
man, I think the answer is not ae, I believe that is the bit ADFM. |
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paivadaniel
Joined: 11 Mar 2011
Posts: 3
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| Posted: Fri Mar 11, 2011 12:35 pm |
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| why psi should change? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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