Hi all I am using the i2C IP Core. In NIOS i would like to get data from an Bosch BME280.

Hi Roman,

Can you share the design?

Your driver & Qsys system looks fine, Need to check the software side.

Regards

Anand

Hi Anand

Find in the attachment:

• C-Code (main.txt)
• Scope picture from an working communication with an Arduino

Somehow strange... today i can`t even get any value, its always empty.

But i get no error, just no data.

Thanks!

Regards

Roman

Hi Roman,

Okay,

For debugging can you try to read slave device address using alt_avalon_i2c_master_target_get.

Refer below link for API example.

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/ug/ug_embedded_ip.pdf

Regards

Anand

Hi Roman,

Is your BME280 SDO pin connected to the ground? check hardware connectivity.

Try to read the slave address without writing it.

Regards

Anand

Hi Anand

Oh i found the wiring issue... (unbelivable :( )

However, now i`m back at my initial problem, that the slave sends me some data that i am not expecting.

In the attachment is an oscilloscope picture, communication via NIOS2. The Slave sends me wrong data, but i a don`t know why and how i can control that from NIOS. (An osci picture from an working communication via arduino is in my first post)

I thought it is a missing initialization step but i can`t find any difference to the examples from Bosch.

      alt_u32 txbuffer[0x200];
 
      alt_u32 rxbuffer[0x200];
      txbuffer[0] = 0xFA; //MSB
      txbuffer[1] = 0xFB; //LSB
      txbuffer[2] = 0xFC; //XLSB
 
  	while (1)
  	{
  		status = alt_avalon_i2c_master_tx_rx(i2c_dev, txbuffer, 1, rxbuffer, 3,    ALT_AVALON_I2C_NO_INTERRUPTS);
 
        usleep(1000000);
    }

Hi,

1. Temperature data may be randomly changing better read some other register.
2. The tx buffer contains the 1-byte address, Is address (FA)correct ???

it should be 2 bytes FA & FB for temperature data.

Instead of reading temp data, read chip id and check if you are getting expected output for debugging.

Buffer[0]=D0;

alt_avalon_i2c_master_tx_rx(i2c_ptr,buffer,1,buffer,1,0);

Regards

Anand