Original Code Snippet from sparkfun,
added YYYY-MM-DD hh:mm:ss output
i used Arduino MEGA-2560 via USB, power from USB,
important: i have to use SPI_MODE3 instead of SPI_MODE1 !!!
SPI_MODE1 delivered bullsh**
PinSetup
RTC – MEGA2560
————–
GND – GND
VCC – 3.3V
SQW – GND (squarewave signal output for interupters)
CLK – 52
MISO – 50
MOSI – 51
SS – 53
#include
const int cs=53; //chip select
void setup() {
Serial.begin(9600);
RTC_init();
//day(1-31), month(1-12), year(0-99), hour(0-23), minute(0-59), second(0-59)
//SetTimeDate(27,4,12,16,5,0); // manuell Zeit setzen, kein 00 benutzen!
}
void loop() {
Serial.println(ReadTimeDate());
delay(1000);
}
//=====================================
int RTC_init(){
pinMode(cs,OUTPUT); // chip select
// start the SPI library:
SPI.begin();
SPI.setBitOrder(MSBFIRST);
SPI.setDataMode(SPI_MODE3); // both mode 1 & 3 should work
//set control register
digitalWrite(cs, LOW);
SPI.transfer(0x8E);
SPI.transfer(0x60); //60= disable Osciallator and Battery SQ wave @1hz, temp compensation, Alarms disabled
digitalWrite(cs, HIGH);
delay(10);
}
//=====================================
int SetTimeDate(int d, int mo, int y, int h, int mi, int s){
int TimeDate [7]={s,mi,h,0,d,mo,y};
for(int i=0; i<=6;i++){
if(i==3)
i++;
int b= TimeDate[i]/10;
int a= TimeDate[i]-b*10;
if(i==2){
if (b==2)
b=B00000010;
else if (b==1)
b=B00000001;
}
TimeDate[i]= a+(b<<4);
digitalWrite(cs, LOW);
SPI.transfer(i+0x80);
SPI.transfer(TimeDate[i]);
digitalWrite(cs, HIGH);
}
}
//=====================================
String ReadTimeDate(){
String temp;
int TimeDate [7]; //second,minute,hour,null,day,month,year
for(int i=0; i<=6;i++){
if(i==3)
i++;
digitalWrite(cs, LOW);
SPI.transfer(i+0x00);
unsigned int n = SPI.transfer(0x00);
digitalWrite(cs, HIGH);
int a=n & B00001111;
if(i==2){
int b=(n & B00110000)>>4; //24 hour mode
if(b==B00000010)
b=20;
else if(b==B00000001)
b=10;
TimeDate[i]=a+b;
}
else if(i==4){
int b=(n & B00110000)>>4;
TimeDate[i]=a+b*10;
}
else if(i==5){
int b=(n & B00010000)>>4;
TimeDate[i]=a+b*10;
}
else if(i==6){
int b=(n & B11110000)>>4;
TimeDate[i]=a+b*10;
}
else{
int b=(n & B01110000)>>4;
TimeDate[i]=a+b*10;
}
}
/* ORIG output
temp.concat(TimeDate[4]); // tag
temp.concat("/") ;
temp.concat(TimeDate[5]); // monat
temp.concat("/") ;
temp.concat(TimeDate[6]); // jahr
temp.concat(" ") ;
temp.concat(TimeDate[2]); // stunde
temp.concat(":") ;
temp.concat(TimeDate[1]); // minute
temp.concat(":") ;
temp.concat(TimeDate[0]); // sekunde
*/
/////
// custom
//temp.concat(" -- ");
String DD = String( TimeDate[4] );
if (DD.length()==1){ DD = "0"+DD; }
String MM = String( TimeDate[5] );
if (MM.length()==1){ MM = "0"+MM; }
String YYYY = String( TimeDate[6] );
if (YYYY.length()==1){ YYYY = "200"+YYYY; }
if (YYYY.length()==2){ YYYY = "20"+YYYY; } // ;o)
if (YYYY.length()==3){ YYYY = "2"+YYYY; } // ;o)
temp.concat( YYYY );
temp.concat( "-" );
temp.concat( MM );
temp.concat( "-" );
temp.concat( DD );
String hh = String( TimeDate[2] );
if (hh.length()==1){ hh = "0"+hh; }
String mm = String( TimeDate[1] );
if (mm.length()==1){ mm = "0"+mm; }
String ss = String( TimeDate[0] );
if (ss.length()==1){ ss = "0"+ss; }
temp.concat(" ");
temp.concat( hh );
temp.concat( ":" );
temp.concat( mm );
temp.concat( ":" );
temp.concat( ss );
//
/////
return(temp);
}
