I understand this could be a bit silly of a doubt. I am using the DS1307 RTC with XIAO BLE Sense nRF52840 to print timestamp. Below is my code-
// Date and time functions using a DS1307 RTC connected via I2C and Wire lib
#include "RTClib.h"
#include "String.h"
RTC_DS1307 rtc;
void setup () {
Serial.begin(57600);
pinMode(LEDR, OUTPUT);
pinMode(LEDG, OUTPUT);
pinMode(LEDB, OUTPUT);
setLedRGB(true, true, true);
delay(1000);
if (! rtc.begin()) {
Serial.println("Couldn't find RTC");
Serial.flush();
while(1) {
delay(500);
setLedRGB(true, false, false);
delay(500);
setLedRGB(false, false, true);
}
}
// rtc.adjust(DateTime(F(__DATE__), F(__TIME__))); //device already setup
}
void loop () {
DateTime now = rtc.now();
if((String(now.year()) == "2000") || (!now.isValid())){
setLedRGB(true,false,false);
Serial.println("Check RTC!");
}
else{
setLedRGB(false,true,false);
Serial.print(now.timestamp());
Serial.println();
delay(3000);
}
}
void setLedRGB(bool red, bool green, bool blue) {
if (!blue) { digitalWrite(LEDB, HIGH); } else { digitalWrite(LEDB, LOW); }
if (!green) { digitalWrite(LEDG, HIGH); } else { digitalWrite(LEDG, LOW); }
if (!red) { digitalWrite(LEDR, HIGH); } else { digitalWrite(LEDR, LOW); }
}
The RTC is connected to 5V/GND of XIAO BLE Sense.
When voltage is measured at VCC/GND, it is 5V with laptop and 1.1 V with battery. (The RTC also has a 3V battery for timekeeping)
I tried connecting 3V, 6V, 9V and 12V battery, but of no difference.
Is there a mistake in my hardware setup?
Edit: I stacked up 7 coin cells to reach 20V, and only then the RTC’s power LED is flowing faintly- but why would it require so much power when the rated power supply is 3.7V around?
PJ