Raspberry PI Model B+ (LCD显示CPU温度)

Title:Raspberry PI Model B+ (LCD显示CPU温度)  --2015-01-29 17:44

买了块连接Raspberry PI Model B+的LCD显示器，上面没写CPU温度，就加工了下。

https://github.com/binerry/RaspberryPi/tree/master/libraries/c/PCD8544

修改后的pcd8544_rpi.c:

https://github.com/Teaing/Raspberrypi/tree/master/PCD8544

/*
=================================================================================
 Name        : pcd8544_rpi.c
 Version     : 0.1

 Copyright (C) 2012 by Andre Wussow, 2012, desk@binerry.de

 Description :
     A simple PCD8544 LCD (Nokia3310/5110) for Raspberry Pi for displaying some system informations.
	 Makes use of WiringPI-library of Gordon Henderson (https://projects.drogon.net/raspberry-pi/wiringpi/)

	 Recommended connection (http://www.raspberrypi.org/archives/384):
	 LCD pins      Raspberry Pi
	 LCD1 - GND    P06  - GND
	 LCD2 - VCC    P01 - 3.3V
	 LCD3 - CLK    P11 - GPIO0
	 LCD4 - Din    P12 - GPIO1
	 LCD5 - D/C    P13 - GPIO2
	 LCD6 - CS     P15 - GPIO3
	 LCD7 - RST    P16 - GPIO4
	 LCD8 - LED    P01 - 3.3V 

================================================================================
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.
================================================================================
 */
#include <wiringPi.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sysinfo.h>
#include "PCD8544.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define TEMP_FILE_PATH "/sys/class/thermal/thermal_zone0/temp"
#define MAX_SIZE 32

// pin setup
int _din = 1;
int _sclk = 0;
int _dc = 2;
int _rst = 4;
int _cs = 3;

// lcd contrast
int contrast = 50;

int main (void)
{
  // print infos
  printf("Raspberry Pi PCD8544 sysinfo display\n");
  printf("========================================\n");

  // check wiringPi setup
  if (wiringPiSetup() == -1)
  {
	printf("wiringPi-Error\n");
    exit(1);
  }

  // init and clear lcd
  LCDInit(_sclk, _din, _dc, _cs, _rst, contrast);
  LCDclear();

  // show logo
  LCDshowLogo();

  delay(2000);

  for (;;)
  {
	  // clear lcd
	  LCDclear();

	  // get system usage / info
	  struct sysinfo sys_info;
	  if(sysinfo(&sys_info) != 0)
	  {
		printf("sysinfo-Error\n");
	  }

	  // uptime
	  char uptimeInfo[15];
	  unsigned long uptime = sys_info.uptime / 60;
	  sprintf(uptimeInfo, "Uptime %ld min.", uptime);

	  // cpu info
	  char cpuInfo[10];
	  unsigned long avgCpuLoad = sys_info.loads[0] / 1000;
	  sprintf(cpuInfo, "CPU %ld%%", avgCpuLoad);

	  // ram info
	  char ramInfo[10];
	  unsigned long totalRam = sys_info.freeram / 1024 / 1024;
	  sprintf(ramInfo, "RAM %ld MB", totalRam);

	  // cpu Temperature
	  char cputemperature[15];
	  float cpu_temperature_Result = Get_Cpu_Temperature();
	  sprintf(cputemperature, "TEMP %.2f ^C", cpu_temperature_Result);

	  // build screen
	  LCDdrawstring(0, 0, "Raspberry Pi:");
	  LCDdrawline(0, 10, 83, 10, BLACK);
	  LCDdrawstring(0, 12, uptimeInfo);
	  LCDdrawstring(0, 20, cpuInfo);
	  LCDdrawstring(0, 28, ramInfo);
	  LCDdrawstring(0, 36, cputemperature);
	  LCDdisplay();

	  delay(10000);
  }

    //for (;;){
  //  printf("LED On\n");
  //  digitalWrite(pin, 1);
  //  delay(250);
  //  printf("LED Off\n");
  //  digitalWrite(pin, 0);
  //  delay(250);
  //}

  return 0;
}

int Get_Cpu_Temperature(void)
{
	int fd;
	double temp = 0;
	char buf[MAX_SIZE];

	// 打开/sys/class/thermal/thermal_zone0/temp
	fd = open(TEMP_FILE_PATH, O_RDONLY);
	if (fd < 0) {
		fprintf(stderr, "failed to open thermal_zone0/temp\n");
		return -1;
		}

	// 读取内容
	if (read(fd, buf, MAX_SIZE) < 0) {
		fprintf(stderr, "failed to read temp\n");
		return -1;
	}

	// 转换为浮点数打印
	temp = atoi(buf) / 1000.0;

	// 关闭文件
	close(fd);
	return temp;
}

　　

编译执行下：

cc -o cpushow pcd8544_rpi.c PCD8544.c  -L/usr/local/lib -lwiringPi

./cpushow

因为℃跟°C显示有问题，就用^代替那个点了。