rpi_temp.c File Reference

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <linux/i2c-dev.h>
#include "midas.h"

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Classes
struct	RPI_TEMP_INFO

Macros
#define	DEV_ID   0x5c
#define	WHO_AM_I   0x0F
#define	CTRL_REG1   0x20
#define	CTRL_REG2   0x21
#define	PRESS_OUT_XL   0x28
#define	PRESS_OUT_L   0x29
#define	PRESS_OUT_H   0x2A
#define	TEMP_OUT_L   0x2B
#define	TEMP_OUT_H   0x2C

Functions
INT	rpi_temp_init (HNDLE hkey, void **pinfo)
INT	rpi_temp_exit (RPI_TEMP_INFO *info)
INT	rpi_temp_get (RPI_TEMP_INFO *info, INT channel, float *pvalue)
INT	rpi_temp (INT cmd,...)

Macro Definition Documentation

CTRL_REG1

#define CTRL_REG1   0x20

Definition at line 36 of file rpi_temp.c.

CTRL_REG2

#define CTRL_REG2   0x21

Definition at line 37 of file rpi_temp.c.

DEV_ID

#define DEV_ID   0x5c

Definition at line 34 of file rpi_temp.c.

PRESS_OUT_H

#define PRESS_OUT_H   0x2A

Definition at line 40 of file rpi_temp.c.

PRESS_OUT_L

#define PRESS_OUT_L   0x29

Definition at line 39 of file rpi_temp.c.

PRESS_OUT_XL

#define PRESS_OUT_XL   0x28

Definition at line 38 of file rpi_temp.c.

TEMP_OUT_H

#define TEMP_OUT_H   0x2C

Definition at line 42 of file rpi_temp.c.

TEMP_OUT_L

#define TEMP_OUT_L   0x2B

Definition at line 41 of file rpi_temp.c.

WHO_AM_I

#define WHO_AM_I   0x0F

Definition at line 35 of file rpi_temp.c.

Function Documentation

rpi_temp()

INT rpi_temp	(	INT	cmd,
			...
	)

Definition at line 134 of file rpi_temp.c.

{
   va_list argptr;
   HNDLE   hKey;
   INT     status, channel;
   float   *pvalue;
   void    *info;
 
   va_start(argptr, cmd);
   status = FE_SUCCESS;
 
   switch (cmd) {
   case CMD_INIT:
      hKey = va_arg(argptr, HNDLE);
      info = va_arg(argptr, void *);
      status = rpi_temp_init(hKey, info);
      break;
 
   case CMD_EXIT:
      info = va_arg(argptr, void *);
      status = rpi_temp_exit(info);
      break;
 
   case CMD_GET:
      info = va_arg(argptr, void *);
      channel = va_arg(argptr, INT);
      pvalue = va_arg(argptr, float *);
      status = rpi_temp_get(info, channel, pvalue);
      break;
 
   default:
      break;
   }
 
   va_end(argptr);
 
   return status;
}

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rpi_temp_exit()

INT rpi_temp_exit

(

RPI_TEMP_INFO *

info

)

Definition at line 88 of file rpi_temp.c.

{
   close(info->fd);
 
   /* free local variables */
   free(info);
 
   return FE_SUCCESS;
}

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rpi_temp_get()

INT rpi_temp_get	(	RPI_TEMP_INFO *	info,
		INT	channel,
		float *	pvalue
	)

Definition at line 100 of file rpi_temp.c.

{
   uint8_t status = 0;
   uint8_t temp_l, temp_h;
   int16_t temp;
   float   deg;
   
   /* Run one-shot measurement (temperature and pressure), the set bit will be reset by the
    * sensor itself after execution (self-clearing bit) */
   i2c_smbus_write_byte_data(info->fd, CTRL_REG2, 0x01);
 
   /* Wait until the measurement is complete */
   do {
      usleep(25*1000);  /* 25 milliseconds */
      status = i2c_smbus_read_byte_data(info->fd, CTRL_REG2);
   }
   while (status != 0);
 
   /* Read the temperature measurement (2 bytes to read) */
   temp_l = i2c_smbus_read_byte_data(info->fd, TEMP_OUT_L);
   temp_h = i2c_smbus_read_byte_data(info->fd, TEMP_OUT_H);
   temp = temp_h << 8 | temp_l;
   
   /* calculate temperature  */
   deg = (42.5 + (temp / 480.0));
   *pvalue = ((int)(deg*100+0.5))/100.0;;
 
   // printf("Temp = %.2f°C\n", *pvalue);
 
   return FE_SUCCESS;
}

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rpi_temp_init()

INT rpi_temp_init	(	HNDLE	hkey,
		void **	pinfo
	)

Definition at line 49 of file rpi_temp.c.

{
   RPI_TEMP_INFO *info;
 
   /* allocate info structure */
   info = calloc(1, sizeof(RPI_TEMP_INFO));
   *pinfo = info;
 
   /* open i2c comms */
   if ((info->fd = open("/dev/i2c-1", O_RDWR)) < 0) {
      perror("Unable to open i2c device");
      exit(1);
   }
 
   /* configure i2c slave */
   if (ioctl(info->fd, I2C_SLAVE, DEV_ID) < 0) {
      perror("Unable to configure i2c slave device");
      close(info->fd);
      exit(1);
   }
 
   /* check we are who we should be */
   if (i2c_smbus_read_byte_data(info->fd, WHO_AM_I) != 0xBD) {
      printf("%s\n", "who_am_i error");
      close(info->fd);
      exit(1);
   }
 
   /* Power down the device (clean start) */
   i2c_smbus_write_byte_data(info->fd, CTRL_REG1, 0x00);
 
   /* Turn on the pressure sensor analog front end in single shot mode  */
   i2c_smbus_write_byte_data(info->fd, CTRL_REG1, 0x84);
 
   return FE_SUCCESS;
}

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