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。

Raspberry PI Model B+ (LCD显示CPU温度)