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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include "lm75.h"
extern int file;
extern void bus_err(int ern);
extern void print_help(void);
unsigned char buf[5];
void lm75_list_all(void)
{
printf(
"00: Temperature data [°C] (reg: 0x00)\n"
"01: Configuration [hex] (reg: 0x01)\n"
"02: Tos (Overtemp) [°C] (reg: 0x03)\n"
"03: Thys (Hysteresis) [°C] (reg: 0x04)\n"
"\n");
}
void lm75_get_data(void)
{
if(write(file, buf, 1) != 1)
{
bus_err(errno);
}
if(read(file, buf, 2) != 2)
{
bus_err(errno);
}
}
float lm75_read_temp(float offset)
{
signed int rawtemp = 0;
float temp;
buf[0] = 0x00;
lm75_get_data();
rawtemp = (buf[0]*256 + buf[1]) >> 5; //(buf[0] << 8), and (>> 5), 11bit device is also supported
if((rawtemp & 0x400) == 0x400) //check if the msb(bit11) is 1 (1024 = 0x400), 2'complement negative number
{
rawtemp = rawtemp - 2048; //2^11 = 2048
}
temp = rawtemp * 0.125 ; //11bit->0.125°C or 9bit->0.5°C
return (temp + offset);
}
float lm75_read_tos(void)
{
int rawtemp = 0;
buf[0] = 0x02;
lm75_get_data();
rawtemp = buf[0]*256 + buf[1];
rawtemp = (rawtemp) >> 7; //9bit data
if((rawtemp & 256) == 256) // check if the msb 2'complement negative number
{
rawtemp = rawtemp - 512 ; // 2^9 = 512;
}
return (rawtemp * 0.5); //9bit -> 0.5 celsius
}
float lm75_read_thys(void)
{
int rawtemp = 0;
buf[0] = 0x03;
lm75_get_data();
rawtemp = buf[0]*256 + buf[1];
rawtemp = (rawtemp) >> 7; //9bit data
if((rawtemp & 256) == 256) // check if the msb 2'complement negative number
{
rawtemp = rawtemp - 512 ; // 2^9 = 512;
}
return (rawtemp * 0.5); //9bit -> 0.5 celsius
}
char lm75_read_conf(void)
{
buf[0] = 0x01;
lm75_get_data();
return buf[0];
}
void lm75_read_all(const char *opts)
{
if(opts != NULL)
{
printf("00:%f\n", lm75_read_temp(strtof(opts, NULL)));
}
else
{
printf("00:%f\n", lm75_read_temp(0.0));
}
printf("01:0x%x\n", lm75_read_conf());
printf("02:%f\n", lm75_read_tos());
printf("03:%f\n", lm75_read_thys());
}
void lm75_read_one(const char *opts)
{
int id;
char *ptr;
id = strtol (opts,&ptr,0); //all format allowed
ptr++; //one separator allowed
switch (id)
{
case 0x00:
printf("00:%f\n", lm75_read_temp(strtof(ptr, NULL)));
break;
case 0x01:
printf("01:0x%x\n", lm75_read_conf());
break;
case 0x02:
printf("02:%f\n", lm75_read_tos());
break;
case 0x03:
printf("03:%f\n", lm75_read_thys());
break;
default:
print_help();
}
}
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