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lloyen1
Guest
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| A to D conversion with the 18f452 |
 Posted: Thu Apr 10, 2008 2:26 pm |
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Hello,
I've been trying to figure out how to program an A to D in C code. I have one working in assembly because I'm a little more comfortable with that language. The problem is I have some difficult calculations to do that would be a nightmare in assembly so I'm converting everything over to C. Here is the working assembly code for the 18f452 and I was just curious if anyone could assist me in converting it over. I have mostly everything commented so its friendly.
Start
clrf TRISB; set PORTB as output
bsf TRISA,0; set PORTA as input
movlw 0x41; (Fosc/8) AD0=set and AD conversion GO
movwf ADCON0
movlw 0x8e; right justified, 7digital and 1 analog channel
movwf ADCON1
bac
nop
nop
nop
nop
bsf ADCON0,GO; set bit 2 of ADCON0 register
nop
nop
spl
btfsc ADCON0,GO; Start A/D
bra spl
; bsf ADCON0,GO
sp2
; btfsc ADCON0,GO
; bra sp2
movff ADRESL,PORTB; send A/D value to PORTB
bra bac
end
Thanks and I'm looking forward to your responses. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Apr 10, 2008 2:37 pm |
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Example:
| Code: | #include <18F452.h>
#device adc=10
#fuses HS,NOWDT,NOPROTECT,BROWNOUT,PUT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
//=================================
void main()
{
int16 result;
setup_adc_ports(AN0);
setup_adc(ADC_CLOCK_DIV_32);
set_adc_channel(0);
delay_us(15);
while(1)
{
result = read_adc();
printf("%LX ", result);
delay_ms(500);
}
} |
This assumes your PIC has a 20 MHz crystal and that your analog input
signal is connected to the AN0 pin on the PIC. It also assumes that you
have your PIC board connected to the serial port on your PC, and that
you are running a terminal program such as HyperTerminal on your PC. |
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ongrongsan
Joined: 01 May 2013
Posts: 1
Location: Malaysia
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| Transfer the analog data to visual basic by through UART and |
| Posted: Wed May 01, 2013 6:40 am |
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| Thank for your coding, if I want transfer the analog data to visual basic by through UART and to control the I/O using visual basic. It's possible? |
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ezflyr
Joined: 25 Oct 2010
Posts: 1019
Location: Tewksbury, MA
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| Posted: Wed May 01, 2013 7:18 am |
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Hi,
Yes, of course it's possible, why not? The PIC can send and receive data via
the UART, and Visual Basic can send and receive data using the PC COM port
and the MSCOMM control. Very simple to do this!
BTW, not that it's particularly relevant, but you are responding to a 5 year old thread!
John |
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