/***************************************************************************
Grab sample temperature and calculate running mean and variance
see http://www.johndcook.com/blog/standard_deviation/
***************************************************************************/
void sampleTemp(Measurement* m, int* semaphorePtr) {
double T, mLast;
m->n++;
if (m->n == 1) { //first measurement
m->M = get_measurement(m->channel, semaphorePtr); //get_measurement first gets internal junction temp then gets TC (20ms delays)
m->S = 0.0;
m->max = m->M;
m->min = m->M;
} else {
T = get_measurement_fast(m->channel, semaphorePtr); //get_measurement_fast just grabs TC value and starts next TC sampling
mLast = m->M;
m->M = mLast + (T - mLast)/m->n; //running mean
m->S = m->S + (T - mLast) * (T - m->M);
m->max = fmax(T, m->max);
m->min = fmin(T, m->min);
}
}
int
main(int argc, char* argv[])
{
int ret;
int i;
uint8_t spi_config=0;
double tval;
int repeat=0;
int period=1;
char fname[128];
char tstring[128];
char tstring2[128];
time_t mytime;
time_t desiredtime;
struct timespec tstime;
int not_finished=1;
int elapsed=0;
int showtime=0;
// initialise GPIO
setup_io();
INP_GPIO(LCD_RS_GPIO); // must use INP_GPIO before we can use OUT_GPIO
OUT_GPIO(LCD_RS_GPIO);
// parse inputs
dofile=0;
if (argc>2)
{
if (strcmp(argv[1], "msg")==0) // print to the lcd
{
spi_config=0;
ret=spi_open(&lcd_fd, 0, spi_config);
if (ret!=0)
{
printf("Exiting\n");
exit(1);
}
lcd_display_string(0,argv[2]);
close(lcd_fd);
exit(0);
}
}
if (argc>1)
{
if (strcmp(argv[1], "-h")==0) // print help
{
printf("%s [sec] [filename]\n", argv[0]);
printf("%s msg <message in quotes>\n", argv[0]);
exit(0);
}
if (strcmp(argv[1], "lcdinit")==0) // initialize the LCD display
{
spi_config=0;
ret=spi_open(&lcd_fd, 0, spi_config);
if (ret!=0)
{
printf("Exiting\n");
exit(1);
}
lcd_init();
close(lcd_fd);
exit(0);
}
if (strcmp(argv[1], "withtime")==0)
{
showtime=1;
}
else
{
sscanf(argv[1], "%d", &period); // period between measurements
repeat=1;
}
if (argc>3)
{
if (strcmp(argv[2], "msg")==0) // print to the lcd
{
spi_config=0;
ret=spi_open(&lcd_fd, 0, spi_config);
if (ret!=0)
{
printf("Exiting\n");
exit(1);
}
lcd_init();
lcd_display_string(0,argv[3]);
lcd_initialised=1;
}
}
}
if (argc>2)
{
strcpy(fname, argv[2]); // file name
dofile=1;
if (argc>4)
{
if (strcmp(argv[3], "msg")==0) // print to the lcd
{
spi_config=0;
ret=spi_open(&lcd_fd, 0, spi_config);
if (ret!=0)
{
printf("Exiting\n");
exit(1);
}
lcd_init();
lcd_display_string(0,argv[4]);
lcd_initialised=1;
}
}
}
if (dofile)
{
outfile=fopen(fname, "w");
}
// open SPI for ADS1118
spi_config |= SPI_CPHA;
ret=spi_open(&ads_fd, 1, spi_config);
if (ret!=0) // SPI error
{
printf("Exiting\n");
exit(1);
}
if (repeat==0)
{
// display a single measurement and exit
tval=get_measurement();
if (showtime)
{
mytime = time(NULL);
sprintf(tstring, "%d", mytime);
unixtime2string(tstring, tstring2);
printf("%s %#.1f\n", tstring2, tval);
}
else
{
printf("%#.1f\n", tval);
}
close(ads_fd);
exit(0);
}
// open up SPI for LCD
spi_config=0;
ret=spi_open(&lcd_fd, 0, spi_config);
if (ret!=0)
{
printf("Exiting\n");
exit(1);
}
if (lcd_initialised==0)
lcd_init();
if (dofile)
{
// line 1 of the output file will contain the three column descriptions
fprintf(outfile, "Time HH:MM:SS,Elapsed Sec,Temp C\n");
}
// Align on an integer number of seconds and get current time
mytime = time(NULL);
tstime.tv_sec=mytime+1;
tstime.tv_nsec=0;
clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &tstime, NULL);
mytime++;
desiredtime=mytime;
signal(SIGINT, sig_handler);
while(not_finished)
{
tval=get_measurement();
for (i=1; i<10; i++)
{
delay_ms(10);
tval=tval+get_measurement_fast();
}
tval=tval/10;
// print the time, elapsed counter and temperature
sprintf(tstring, "%d", mytime);
unixtime2string(tstring, tstring2);
if (mytime==desiredtime)
{
printf("%s %d %#.1f\n", tstring2, elapsed, tval);
if (dofile)
{
fprintf(outfile, "%s,%d,%#.1f\n", tstring2, elapsed, tval);
fflush(outfile);
}
desiredtime=desiredtime+period;
}
sprintf(tstring, "%s %#.1f", tstring2, tval);
lcd_display_string(1, tstring);
// now we sleep for a certain time
mytime++;
tstime.tv_sec=mytime;
elapsed++;
clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &tstime, NULL);
}
close(ads_fd);
// LCD requires opposite clock polarity
spi_config=0;
ret=spi_open(&lcd_fd, 0, spi_config);
if (ret!=0)
{
printf("Exiting\n");
exit(1);
}
lcd_init();
lcd_clear(); // LCD clear
lcd_display_string(0,"Hello"); // display "ADS1118"
close(lcd_fd);
return(0);
}
