Re: Problem with i2c and fpga

Altera_Forum · ‎02-19-2012

Hi,

I'm using an Altera Cyclone ll as fpga with a nios to communicate with a sfr08 sensor.

I downloaded the opencore IP found in the wiki but i have a problem with it.

I integrated it in the SOPC builder and generated the processor without problem, also the bdf file compiles without errors.

I read the documentation but i'm not able to communicate with the internal registers of the module, probably due to a wrong memory address.

Here is the code i'm using:


//the i2c module in the sopc has the address 0x00101000;
volatile int * red_LED_ptr = (int *) 0x00101040; // red LED address
int * Control = (int *) 0x00101002;
int * Send = (int *) 0x00101003;
int * Command = (int *) 0x00101004;
volatile int * Receive = (int *)0x00101003;
volatile int * Status = (int *)0x00101004;
int main(void)
{
  int stato;
  *(Control) = 0x80;                 //enable the i2c core 
  * (Command) = 0x90;             //set STA bit and WR bit
  * (Send) = 0xa0;                   //device address with last bit 0 (write)
  do{
     stato = * (Status);}            //check status register for the TIP bit
  while ((stato & 0x02 )!= 0x00); // TIP == 0 --> trasimssion complete
  if ((stato & 0x80) == 0x00){     // if ack send register address
     * (Send) = 0x00;                 // register address
     * (Command) = 0x10;           //set STA bit and WR bit
  }
  do{                                     
     stato = * (Status);}            // TIP control as before
  while ((stato & 0x02 )!= 0x00) ;
  if ((stato & 0x80) == 0x00){    //if ack  send data
     * (Send) = 0x51;                //data to write
     * (Command) = 0x50;           //set STA bit and WR bit
  }
  do{
     stato = * (Status);}           // TIP control as before
  while ((stato & 0x02 )!= 0x00) ;
  *(red_LED_ptr)= stato;          // put the status register (with ack bit) on led
}

Any suggestion will be appreciate, thanks

Altera_Forum · ‎02-20-2012

You don't need to set pointers to component addresses. Those addresses are defined in system.h file, so use them instead. Check the core examples, they're very informative.

Altera_Forum · ‎02-21-2012

Thanks for the suggestion, i should think to it by myself.

Even if i can't find the file system.h i was able compile the code without it and now it works.

Thanks again.

Altera_Forum · ‎02-21-2012

It's in the BSP directory.