[SOLVED] 24C32 read and write isses

[Rendon]

I cannot seem to write to this device. I am using library protocols in MikroC to address this device. I am able to address the smaller 24C02 without any difficulty. I have a small veroboard with 3 I^2C devices + dip switch arrays to preset device addresses.

I know that the 24C32 is addressed correctly because it returns a value of 255 only when its address corresponds to my variable set in code. If I remove the device or change its address, it does not return the value of 255. I am using the identical protocol as I do with the 24C02. There is no change in code. I am prefixing the device address with 1010 ****. The ONLY difference is the chip. Below is my code. I am using eeprom data address #9. Initially, I thought the device might be faulty, so I swapped it out, but to no avail. The value in variable "test" is what I am trying to write to the 24C32. Again, this code works perfectly on the 24C02. Any idea as to why that is? I'm stumped. (These are both Atmel devices.)

---

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
char   atmel4 = 0xa6,  test=0x77,      
 
 
 
void main(){
 
  PORTB = 0;
  TRISB = 0;                 // Configure PORTB as output
 
  I2C1_Init(100000);         // initialize I2C communication
  
//write protocol
  
  I2C1_Start();              // issue I2C start signal
  I2C1_Wr(atmel4);             // send byte via I2C  (device address + W)
  I2C1_Wr(9);                // send byte (address of EEPROM location)
  I2C1_Wr(test);             // send data (data to be written)
  I2C1_Stop();               // issue I2C stop signal
 
  
//Read protocol
 
  Delay_100ms();
 
  I2C1_Start();              // issue I2C start signal
  I2C1_Wr(atmel4);             // send byte via I2C  (device address + W)
  I2C1_Wr(9);                // send byte (data address)
  I2C1_Repeated_Start();     // issue I2C signal repeated start
  I2C1_Wr(atmel4+1);             // send byte (device address + R)
  PORTB = I2C1_Rd(0u);       // Read the data (NO acknowledge)
  I2C1_Stop();               // issue I2C stop signal
}

---

 

[papunblg]

Dont let the control exit the main()

- - - Updated - - -

Dont let the control exit the main()

 

[Rendon]

Do you mean don't use library functions? I am new to C.

- - - Updated - - -

Do you mean don't use library functions? I am new to C.

 

[Baas Rietrot]

I think he means:

---

Code C - [expand]
1
2
3
4
5
6
7
void main(){
 
// Your code
 
while(1){};     // <-- add this at the bottom of your code
 
}

---

When your code needs to loop:

---

Code C - [expand]
1
2
3
4
5
6
7
8
void main(){
 
while(1){
 
// Code here
 
    };
}

---

 

[papunblg]

Yes. When you run a C program in a PC, the OS takes control when your program ends. But that does not happen in case of a microcontroller. And the mc becomes unstable(kind of).
There may be other problems in your code but correct the structure of the program first.

 

[yuvko]

you have 2 address bytes in 24C32 not 1 like in the 24c02

 

[papunblg]

https://www.edaboard.com/threads/233645/#post997047

 

[Rendon]

Yes, you're absolutely right. It occurred to me while I was trying to sleep. I got up and added a second address write and it solved the problem.