rfivet/stm32bringup
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ADC calibration application to experiment with the internal temperature sensor using a DS18B20 as reference.

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This commit is contained in:
Renaud 2021-02-09 15:36:03 +08:00
parent 8c9c4e6d3e
commit 4098e6e6af
2 changed files with 79 additions and 1 deletions
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3
Makefile
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@ -39,7 +39,8 @@ PROJECT = f030f4
#SRCS = startup.txeie.c txeie.c uptime.c
#SRCS = startup.txeie.c gpioa.c dht11main.c dht11.c
#SRCS = startup.txeie.c gpioa.c ds18b20main.c ds18b20.c
SRCS = startup.txeie.c adc.c adcmain.c
#SRCS = startup.txeie.c adc.c adcmain.c
SRCS = startup.txeie.c adc.c adccalib.c ds18b20.c
OBJS = $(SRCS:.c=.o)
LIBOBJS = printf.o putchar.o puts.o
CPU = -mthumb -mcpu=cortex-m0

77
adccalib.c Normal file
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@ -0,0 +1,77 @@
/* adccalib.c -- ADC calibration of internal temperature sensor */
/* Copyright (c) 2020-2021 Renaud Fivet */
#include <stdio.h>
#include "system.h" /* uptime, adc_vnt() */
#include "ds18b20.h" /* ds18b20_() */
#define ABS( i) ((i < 0) ? -i : i)
static void track( short *minp, short *maxp, short val) {
if( val < *minp)
*minp = val ;
if( val > *maxp)
*maxp = val ;
}
int main( void) {
unsigned last = 0 ;
short calV, calC ;
short minC, maxC ; /* Track temperature from DS18B20 */
short minV, maxV ; /* Track ADC raw Vref */
short minT, maxT ; /* Track ADC raw Tsense */
minC = minV = minT = 0x7FFF ;
maxC = maxV = maxT = -32768 ;
/* Initialize ADC and fetch calibration values */
adc_vnt( VNT_INIT, &calV, &calC) ;
printf( "%u, %u\n", calV, calC) ;
int tconst = 6660 * calV / calC ;
/* Initialize DS18B20 and initiate temperature conversion */
ds18b20_init() ;
ds18b20_resolution( 12) ; /* Set highest resolution: 12 bits */
ds18b20_convert() ; /* start temperature conversion */
/* main acquisition loop, reads samples every seconds */
for( ;;)
if( uptime == last)
yield() ;
else {
short Vsample, Csample ;
last = uptime ;
/* Track DS18B20 temperature readings */
switch( ds18b20_fetch( &Csample)) {
case DS18B20_SUCCESS:
track( &minC, &maxC, Csample) ;
printf( "%i.%i, %i, %i, ", Csample / 10, ABS( Csample % 10),
minC, maxC) ;
break ;
case DS18B20_FAIL_TOUT:
printf( "Timeout, ") ;
break ;
case DS18B20_FAIL_CRC:
printf( "CRC Error, ") ;
}
ds18b20_convert() ; /* start temperature conversion */
/* Track Internal Temperature Sensor readings */
adc_vnt( VNT_RAW, &Vsample, &Csample) ;
track( &minV, &maxV, Vsample) ;
track( &minT, &maxT, Csample) ;
printf( "%i, %i, %i, %i, %i, %i, %i, %i, ",
calV, Vsample, minV, maxV,
calC, Csample, minT, maxT) ;
Csample = 3630 - (1 + tconst * Csample / Vsample) / 2 ;
Vsample = (660 * calV / Vsample + 1) / 2 ;
printf( "%i.%i, %i.%i\n", Vsample / 100, ABS( Vsample % 100),
Csample / 10, ABS( Csample % 10)) ;
}
}
/* end of adccalib.c */