How to write data ds1307 for 8051

[FvM]

void main ()
{
    InitI2c();
    StartI2c();
    ACK = write_i2c(unsigned char DS1307_SECONDS);;
}

After start, you'll send the device address first.

No type cast needed for DS1307_SECONDS. The correct type cast syntax would be

write_i2c((unsigned char) DS1307_SECONDS);

write_i2c() might need a delay to keep I2C timing, depending on the processor speed.

 

[ansh11]

After start, you'll send the device address first.

write_i2c() might need a delay to keep I2C timing, depending on the processor speed.

It would something this

---

Code C - [expand]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
#include <reg51.h>
 
//Define the Pin for the I2c 
sbit SDA_BUS = P2^0;
sbit SCL_BUS = P2^1;
 
#define I2C_DELAY    50         //Delay for I2c
#define DS1307_ADDRESS  0xD0    //  the device address
#define DS1307_SECONDS  0x00    //  DS1307 register addresses
 
void InitI2c(void);
void StartI2c(void);
void RepeatedStartI2c(void);
void StopI2c(void);
void delay(unsigned int);
unsigned char write_i2c(unsigned char);
 
/* This function provide the delay which is used in clock generation.*/
void delay(unsigned int d)
{
    unsigned int i;
    for(i=0; i<d; i++);
}
 
/*This function  use to make the data line and clock line idle to put the both line high
*/
void InitI2c(void)
{
    SDA_BUS =1;
    SCL_BUS =1;
}
 
/*This function performs the start operation to initiate the communication.
*/
void StartI2c(void)
{
    SDA_BUS  = 1;
    SCL_BUS  = 1;
    delay(I2C_DELAY);
    SDA_BUS  = 0;
    delay(I2C_DELAY);
}
 
/*When master want to stop the communication then it will assert the stop condition to the i2c bus.*/
 
void StopI2c(void)
{
    SCL_BUS  = 0;
    delay(I2C_DELAY/2);
    SDA_BUS  = 0;
    delay(I2C_DELAY/2);
    SCL_BUS  = 1;
    delay(I2C_DELAY/2);
    SDA_BUS  = 1;
    delay(I2C_DELAY);
}
 
/*When master does not want to relaese the control from the bus then it assert the repeated
start condition on the i2c bus*/
 
void RepeatedStartI2c()
{
    SCL_BUS  = 0;
    delay(I2C_DELAY/2);
    SDA_BUS  = 1;
    delay(I2C_DELAY/2);
    SCL_BUS  = 1;
    delay(I2C_DELAY/2);
    SDA_BUS  = 0;
    delay(I2C_DELAY);
}
 
//send a byte and get ack 
unsigned char write_i2c(unsigned char byte);
{
     unsigned char i, ack_bit;
    
     for (i = 0; i < 8; i++) {
        if ((byte & 0x80) == 0)
            SDA_BUS = 0;
        else
            SDA_BUS = 1;
        SCL_BUS = 1;
        SCL_BUS = 0;
        byte<<=1;
     }
 
     SDA_BUS = 1;
     SCL_BUS = 1;
     ack_bit = SDA_BUS;
     SCL_BUS = 0;
 
     return ack_bit;
}
void main ()
{
    char Time_Seconds = 0x00;
    InitI2c();
    StartI2c();
 
    ACK = write_i2c(unsigned char DS1307_ADDRESS );
    ACK = write_i2c(unsigned char DS1307_SECONDS);;
}

---

i want to send some value to DS1307_SECONDS

char Time_Seconds = 0x00;

Now how to send this value?

 

[KlausST]

Hi,

An edaboard forum search for "DS1307 8051" gives about 100 hits. Many thousands if you do an internet search.
May I ask why you don't refer to one of the available codes?
It's how a forum is meant to work: One starts a thread with a problem ... many others gain from the information.

I see nothing in your thread that isn't already discussed in the existing threads.

Klaus

 

[FvM]

i want to send some value to DS1307_SECONDS

char Time_Seconds = 0x00;

Now how to send this value?

I believe, the question has been already answered along this thread, e.g. in post #14.

---

Code C - [expand]
1
2
3
4
5
6
7
8
9
10
11
StartI2c();
ACK = write_i2c(DS1307_ADDRESS );
if (ACK == 1)
{
  StopI2C();
  ...
}
else
{
  ACK = write_i2c(DS1307_SECONDS);
  ACK = write_i2c(Time_Seconds);

---

}

 

[ansh11]

Hi,

An edaboard forum search for "DS1307 8051" gives about 100 hits. Many thousands if you do an internet search.
May I ask why you don't refer to one of the available codes?
It's how a forum is meant to work: One starts a thread with a problem ... many others gain from the information.

I see nothing in your thread that isn't already discussed in the existing threads.

Klaus

It's not that i haven't seen the code I have seen, but I do not understand the whole code. I though that I would have to go one step at a time to get to my destination

- - - Updated - - -

I believe, the question has been already answered along this thread, e.g. in post #14.

}

No you misunderstood

DS1307_SECONDS 0x00 //address

char Time_Seconds = 0x00; // value

I want to store 0x00 value at DS1307_SECONDS register

 

[FvM]

No you misunderstood

Not at all. The code does what you want.

Plenty of explanation now. I think it's time to start coding and debugging.

 

[KlausST]

Hi,

No you misunderstood

DS1307_SECONDS 0x00 //address

char Time_Seconds = 0x00; // value

I want to store 0x00 value at DS1307_SECONDS register

...this exactly is what's written in post#14 ... or in figure6 of the datasheet.

It's not that we misunderstand you....

Klaus