You can copy / paste the code below if you’re having issues with typos or want a shortcut. However I recommend that you follow along in the tutorial to understand what is going on!
#include <SPI.h>
/*
* 1 - Setup the clock such that we get a SQW output
* 2 - Set the time of the clock
* 3 - Read the time of the clock
*/
int chipSelect = 8 ;
int intFreq = 4 ;
#define WRITE_CONTROL_REG 0x8E
#define READ_CONTROL_REG 0x0E
#define WRITE_TIME_REG 0x80
#define READ_TIME_REG 0x00
typedef struct timeParameters{
uint8_t ss ;
uint8_t mm ;
uint8_t hh ;
uint8_t dy ;
uint8_t d ;
uint8_t m ;
uint8_t y ;
} ;
void RTC_init(int chipSelect, int intFreq){
/*
* The DS3234 offers four output frequencies:
* Options:
* 1: 1 Hz
* 2: 1.024 kHz
* 3: 4.096 kHz
* 4: 8.192 kHz
* 5: OFF
*/
pinMode(chipSelect, OUTPUT) ;
digitalWrite(chipSelect, LOW) ;
SPI.transfer(READ_CONTROL_REG) ;
byte originalConfig = SPI.transfer(0x00) ;
digitalWrite(chipSelect, HIGH) ;
delay(10) ;
byte configModifier ;
byte newConfig ;
if (intFreq == 5){
configModifier = 0b10111111 ;
newConfig = configModifier & originalConfig ;
}
else if(intFreq < 5){
uint8_t freqOption = intFreq - 1 ;
configModifier = (freqOption << 3) | 0b01000000 ;
newConfig = configModifier | (originalConfig & 0b11100011) ;
}
digitalWrite(chipSelect, LOW) ;
SPI.transfer(WRITE_CONTROL_REG) ;
SPI.transfer(newConfig) ;
digitalWrite(chipSelect, HIGH) ;
delay(10) ;
}
static uint8_t convertValueIN(uint8_t value){
uint8_t convertedVal = value - 6 * (value >> 4) ;
return convertedVal ;
}
static uint8_t convertValueOUT(uint8_t value){
uint8_t convertedVal = value +6 * (value / 10) ;
return convertedVal ;
}
void setTime(int chipSelect, timeParameters *timeVals){
pinMode(chipSelect, OUTPUT) ;
digitalWrite(chipSelect, LOW) ;
SPI.transfer(WRITE_TIME_REG) ;
SPI.transfer(convertValueOUT(timeVals->ss)) ;
SPI.transfer(convertValueOUT(timeVals->mm)) ;
SPI.transfer(convertValueOUT(timeVals->hh)) ;
SPI.transfer(convertValueOUT(timeVals->dy)) ;
SPI.transfer(convertValueOUT(timeVals->d)) ;
SPI.transfer(convertValueOUT(timeVals->m)) ;
SPI.transfer(convertValueOUT(timeVals->y)) ;
digitalWrite(chipSelect, HIGH) ;
delay(10) ;
}
void readTime(int chipSelect, timeParameters *timeVals){
pinMode(chipSelect, OUTPUT) ;
digitalWrite(chipSelect, LOW) ;
SPI.transfer(READ_TIME_REG) ;
timeVals->ss = convertValueIN(SPI.transfer(0x00)) ;
timeVals->mm = convertValueIN(SPI.transfer(0x00)) ;
timeVals->hh = convertValueIN(SPI.transfer(0x00)) ;
timeVals->dy = convertValueIN(SPI.transfer(0x00)) ;
timeVals->d = convertValueIN(SPI.transfer(0x00)) ;
timeVals->m = convertValueIN(SPI.transfer(0x00)) ;
timeVals->y = convertValueIN(SPI.transfer(0x00)) ;
digitalWrite(chipSelect, HIGH) ;
delay(10) ;
}
timeParameters example_vals = {
50,
59,
23,
1,
31,
12,
10
} ;
uint32_t timeTrigs = 0 ;
void timeFunc(){
timeTrigs += 1 ;
}
void setup() {
SPI.begin() ;
SPI.setBitOrder(MSBFIRST) ;
SPI.setDataMode(SPI_MODE1) ;
Serial.begin(9600) ;
delay(10) ;
RTC_init(chipSelect, intFreq) ;
setTime(chipSelect, &example_vals) ;
attachInterrupt(0, timeFunc, RISING) ;
}
void loop() {
delay(1000) ;
readTime(chipSelect, &example_vals) ;
Serial.print("Time: ") ;
Serial.print(example_vals.hh) ;
Serial.print(":") ;
Serial.print(example_vals.mm) ;
Serial.print(":") ;
Serial.println(example_vals.ss) ;
Serial.print("Date: ") ;
Serial.print(example_vals.y) ;
Serial.print("/") ;
Serial.print(example_vals.m) ;
Serial.print("/") ;
Serial.println(example_vals.d) ;
Serial.print("Time Triggers: ") ;
Serial.println(timeTrigs) ;
timeTrigs = 0 ;
}
