real time clock (ds1307)

[vead]

hello

I am interfacing RTC with microcontroller and LED.
actually I have prototyping KIt (cortex m0). I only need c code.
I want to control LED using real time clock via I2c pins

Set alarm for 5 second (automatically turn on LED for 5 second )
Set alarm for 3 minute (automatically turn on LED for 3 minute)
Set alarm for 1 hours (automatically turn on Led for 1 hours )

SCL connected with P3.5;
SDA connected with P3.1;
LED connected with P1.6

LED will read the data form ds1307 via i2c pins

I did google searched but I did not find related to LED. I am not using LCD
can someone explain with small example. How to write c code for minute , hours , day ?

 

[ud23]

you can search the forum have many ds1307 code. for LED operating use three variable for second,minute,hour when timer start increment second variable and turn on led. if second = 5 then turn the led gpio off.and for minutes increment the minute variable when second variable rich to 59.and do same like for hour.

 

[vead]

ok , I want to send data from device to ds1307.

example
1. Send a start sequence
2. Send 0xD0 ( address of the DS1307 )
3. Send 0x00 (address of seconds register)
4. Send 0x10 ((10 data as 10 second)
5. Send stop sequence

void I2C_Init()
{
	SDA = 1;
	SCL = 1;
}

void I2C_Start()        // start I2C
{
	SDA = 0;
	SCL = 0;
}

I2C_Send(0xD0);      // address of the DS1307 )
I2C_Send(0x00);      // address of seconds register
I2C_Send(0x10);       // 10 data as 10 second

void I2C_Stop()    // stop I2C
{
	SCL = 0;
	SDA = 0;
	SCL = 1;
	SDA = 1;
}

how to write from device ?

 

[ud23]

**broken link removed**
**broken link removed**

 

[vead]

**broken link removed**
**broken link removed**

I saw that sample code. Now I am trying to write myself

                void I2C_Init()         //
                {
                    SDA = 1;
                    SCL = 1;
                }

                void I2C_Start()       // start I2C
                {
                    SDA = 0;
                    SCL = 0;
                }

                I2C_write()               //  send data to Ds1307
                {
                I2C_write(0xD0);      // address of the DS1307 )
                I2C_write(0x00);      // address of seconds register
                I2C_write(0x10);       // 10 data as 10 second
                }

                void I2C_Ack()
                {
                    SDA = 0;
                    SCL = 1;
                    SCL = 0;
                    SDA = 1;

                void I2C_Stop()    // stop I2C
                {
                    SCL = 0;
                    SDA = 0;
                    SCL = 1;
                    SDA = 1;
                }

                void I2C_Start()
                {
                    SDA = 0;
                    SCL = 0;
                }

                I2C_read()
                {
                I2C_write(0xD1);      // address of the DS1307 )
                I2C_write(0x00);      // address of seconds register
                I2C_write(0x10);       // 10 data as 10 second
                }

                void I2C_Nak()
                {
                    SDA = 1;
                    SCL = 1;
                    SCL = 0;
                    SDA = 1;
                }

                void I2C_Stop()    // stop I2C
                {
                    SCL = 0;
                    SDA = 0;
                    SCL = 1;
                    SDA = 1;
                }

how to set alarm for led?

 

[ud23]

you can do it by setting the alarm mode for ds1307 you can read its data sheet you just get all the answers you are looking for.

 

[vead]

you can do it by setting the alarm mode for ds1307 you can read its data sheet you just get all the answers you are looking for.

I saw both file that you posted in post #4. I did not see the any code for LED. thats why I tried to make myself

basic algorithm to understand
1. start i2c
2 write to ds1307
3 write address of ds1307
4 write address of register
5 write address of data ( second, minute, hours )
6 stop i2c
7 start i2c
8 read from ds1307
9 read address of ds1307
10 read address of register
11 read data (seconds minute )
12 stop i2c
13 led ..............?

how does alarm set for LED ?

 

[ud23]

what is the reference point for the counting or start of alarm? I mean when you know that we need to start the counter for 5sec ,3min,1 hour?you need to turn on the alarm mode then set the desired timing.

and just a question do you just have these three fixed alarm 5sec,3 minute,1 hour ? what is your led functionality? if its cyclic then why you need a rtc? not clear about your application.