Freenove Ultimate Starter Kit - Page 224

Chapter 20 LCD1602
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#define RW BASE+1
#define EN BASE+2
#define LED BASE+3
#define D4 BASE+4
#define D5 BASE+5
#define D6 BASE+6
#define D7 BASE+7
int lcdhd; // used to handle LCD
void printCPUTemperature(){// subfunction used to print CPU temperature
FILE *fp;
char str_temp[15];
float CPU_temp;
// CPU temperature data is stored in this directory.
fp= fopen("/sys/class/thermal/thermal_zone0/temp","r");
fgets( str_temp,15,fp); // read file temp
CPU_temp = atof( str_temp)/1000.0; // convert to Celsius degrees
printf("CPU's temperature : %.2f \n", CPU_temp);
lcdPosition(lcdhd,0,0); // set the LCD cursor position to (0,0)
lcdPrintf(lcdhd,"CPU:%.2fC",CPU_temp);// Display CPU temperature on LCD
fclose(fp);
}
void printDataTime(){//used to print system time
time_t rawtime;
struct tm * timeinfo;
time(&rawtime);// get system time
timeinfo = localtime(&rawtime);// convert to local time
printf("%s \n", asctime(timeinfo));
lcdPosition(lcdhd,0,1);// set the LCD cursor position to (0,1)
lcdPrintf(lcdhd,"Time:%d:%d:%d",timeinfo->tm_hour,timeinfo->tm_min,timeinfo->tm_sec);
//Display system time on LCD
}
int main( void){
int i;
if(wiringPiSetup() == -1){ //when initialize wiring failed, print message to screen
printf("setup wiringPi failed !");
return 1;
}
pcf8574Setup(BASE,pcf8574_address);// initialize PCF8574
for(i=0;i<8;i++){
pinMode(BASE+i,OUTPUT); // set PCF8574 port to output mode
}
digitalWrite(LED,HIGH); // turn on LCD backlight