RTC set time in code

I have a Seeeduino v2.12 with shield 4.0 and DS1307
I am new to this but have done some programming before in Pasca and C++

I have forund a code that fulfield my need. Actualy I am also going to use it for Aquarium lightning control. LED-ofcause.
I can compile the code and upload it without problems but I get a strange output.
I measure between 0.2v and 1.6v on PWM 9- increasing and rigth after decreasing…then increasing and so on.

I expected to see from 0 to 3.3v, then stabile.

I have not change anything in the code. Do I have to?
How do the board know the time.

And just a small ad question: how do I put the code nicely in to the message.?

// Pins to control LEDs. Change these if you're using different pins.
int blueLed = 9;     // LED PWM channel for blues
int whiteLed = 10;   // LED PWM channel for whites

// Set up RTC

#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68

// RTC variables
byte second, rtcMins, oldMins, rtcHrs, oldHrs, dayOfWeek, dayOfMonth, month, year;

// Other variables. These control the behavior of lighting. Change these to customize behavoir
int minCounter = 0;         // counter that resets at midnight. Don't change this.
int blueStartMins = 0;    // minute to start blues. Change this to the number of minutes past
                            //    midnight you want the blues to start.
int whiteStartMins = 0;   // minute to start whites. Same as above.
int bluePhotoPeriod = 1240;  // photoperiod in minutes, blues. Change this to alter the total
                            //    photoperiod for blues.
int whitePhotoPeriod = 1240; // photoperiod in minutes, whites. Same as above.
int fadeDuration = 5;      // duration of the fade on and off for sunrise and sunset. Change
                            //    this to alter how long the fade lasts.
int blueMax = 200;          // max intensity for blues. Change if you want to limit max intensity.
int whiteMax = 255;         // max intensity for whites. Same as above.

/****** LED Functions ******/
//function to set LED brightness according to time of day
//function has three equal phases - ramp up, hold, and ramp down
void setLed(int mins,    // current time in minutes
            int ledPin,  // pin for this channel of LEDs
            int start,   // start time for this channel of LEDs
            int period,  // photoperiod for this channel of LEDs
            int fade,    // fade duration for this channel of LEDs
            int ledMax   // max value for this channel
            )  {
  if (mins > start && mins <= start + fade)  {
    analogWrite(ledPin, map(mins - start, 0, fade, 0, ledMax));
    if (mins > start + period && mins <= start + period - fade)  {
    analogWrite(ledPin, ledMax);
    if (mins > start + period - fade && mins <= start + period)  {
    analogWrite(ledPin, map(mins - start + period - fade, 0, fade, ledMax, 0));

/***** RTC Functions *******/
// Convert normal decimal numbers to binary coded decimal
byte decToBcd(byte val)
  return ( (val/10*16) + (val%10) );

// Convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
  return ( (val/16*10) + (val%16) );

// 1) Sets the date and time on the ds1307
// 2) Starts the clock
// 3) Sets hour mode to 24 hour clock
// Assumes you're passing in valid numbers.
void setDateDs1307(byte second,  // 0-59
                   byte minute,        // 0-59
                   byte hour,          // 1-23
                   byte dayOfWeek,     // 1-7
                   byte dayOfMonth,    // 1-28/29/30/31
                   byte month,         // 1-12
                   byte year)          // 0-99

// Gets the date and time from the ds1307
void getDateDs1307(byte *second,
          byte *minute,
          byte *hour,
          byte *dayOfWeek,
          byte *dayOfMonth,
          byte *month,
          byte *year)

  Wire.requestFrom(DS1307_I2C_ADDRESS, 7);

  *second     = bcdToDec(Wire.receive() & 0x7f);
  *minute     = bcdToDec(Wire.receive());
  *hour       = bcdToDec(Wire.receive() & 0x3f);
  *dayOfWeek  = bcdToDec(Wire.receive());
  *dayOfMonth = bcdToDec(Wire.receive());
  *month      = bcdToDec(Wire.receive());
  *year       = bcdToDec(Wire.receive());

void setup()  {
// init I2C  

/***** Main Loop ***********/
void loop()  {
  // get time from RTC and put in hrs and mins variables
  getDateDs1307(&second, &rtcMins, &rtcHrs, &dayOfWeek, &dayOfMonth, &month, &year);
  minCounter = rtcHrs * 60 + rtcMins;

  // determine if it is day or night, and act accordingly
  if ((minCounter > blueStartMins || minCounter > whiteStartMins)
           && (minCounter < blueStartMins + bluePhotoPeriod || minCounter < whiteStartMins + whitePhotoPeriod))  {   //day
    // set LED states
    setLed(minCounter, blueLed, blueStartMins, bluePhotoPeriod, fadeDuration, blueMax);
    setLed(minCounter, whiteLed, whiteStartMins, whitePhotoPeriod, fadeDuration, whiteMax);
  else  {   //night
    analogWrite(blueLed, 0);
    analogWrite(whiteLed, 0);
  // Get ready for next iteration of loop

And just a small ad question: how do I put the code nicely in to the message.?

When you post code, click the button on the top row with the # on it. Then, paste the code.

Or paste the code, then select all of it, then press the # button.

You can also modify your previous post to post the code properly. And, it would be appreciated if you would.

The cyclic nature of the voltage measured on the PWM pin is probably due to your multimeter averaging the output collected over some period of time as your code changes the PWM duty cycle from 0 to 100%.

How do the board know the time.

If you’ve never loaded a sketch to set the time on the RTC, it starts from 00:00:00 on 00/00/0000. If you have loaded a sketch that sets the time on the RTC, the function of the RTC is to keep updating the current time, so that when you call the get function at the start of loop, to get the time, the RTC can return the correct time.

ok. thx

Better now?

I have inplantet a lot of time things now, så I kan see the time in the serial monitor. It helps alot. For some reason the code is not working for me, so now I whrite my own. It is only fade in - hold - fade out, at given time.