PIC ADC
I have used the new 18F8723 with 12 bit A/D.
To get the the full resolution, you have to use DEFINE
"DEFINE ADC_BITS 10"
Because PBP only "knows about" 8 and 10 bit converters.
If the DEFINE is missing or not interpreted properly in the
compiler, it will default to 8 bits.
If you use the line above at the top of your program,
and have a 12-bit converter in your chip, the result will
indeed have a full 12 bits of resolution.
Charles Linquist
long map(long x, long in_min, long in_max, long out_min, long out_max)
{
return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}
PWMDuty = 100 + (ADCInValue ** 39322) ' Same as 100 + ADCInValue * 0.600006 but likely faster than 100+ADCInValue*6/10
Think of the ** operator as multiplying by units of 1/65536. 0.6*65536=39322.
' m = 0.1219
' b = 24.9
' y = (ADC * 0.1219) - 24.9
' ADC = 1023
' y = 99.8
M CON 1219 'm = 0.1219 * 10,000
B CON 249 'b = 24.9 * 10
ADC VAR WORD 'INPUT FROM SENSOR
Y VAR WORD 'PSI
Z VAR WORD 'DUMMY VAR
Z1 VAR WORD 'DUMMY VAR
START:
ADC = 1023 'FULL SCALE HARD CODED, NO SENSOR
Z = ADC * M
Z1 = DIV32 1000
Y = Z1 - B
LCDOUT $FE,1,"PSI= ",DEC Y/10,".",DEC2 Y//100
PAUSE 250
GOTO START
29 mainloop:
30 ADCIN 3, adval ' Read channel 3 to adval (0-1023)
31 adval = (adval */ 500)>>2 ' Equates to: (adval * 500)/1024
32
