ADAU1761 i2c address issue

Hi,

I have moved this discussion from the Processors and DSP community to the SigmaDSP Processors and SigmaStudio Development Tool community. Please continue the discussion here.

Regards,
Craig.

Hello Hossein,

I took a look into your issue and responded at the following thread:

I2C address for ADAU1761

Regards,

-John

Hi again,

You mentioned you had some problems implementing I2C reads on the ADAU1761. I created a simple test in SigmaStudio to read a DC value using a DSP readback cell, which generates an I2C read request.

For example, lets say we want to generate a DC value as - 8 (minus eight) in 5.23 format. After compiling/downloading and clicking on the green "READ" button, we read back the hex value 0xC000000 (as expected)

The SigmaStudio capture window also displayed the following contents for the I2C transaction after reading the value:

The ADAU1761 datasheet I2C read shows a sequence with chip address byte, followed by two sub-address bytes, then a repeat start comman by the master to generate another chip address, followed by reading the data.

Examining the I2C bus activity when executing the DSP readback command, I see the chip address, followed by the subaddress (address 0x0009 for the DSP readback, generated by the SigmaStudio compiler). After this sub-address, I observe a 3.6 millisecond delay before reading the memory content data.

Chip Address/Sub Address Setup (zoomed in version of the first I2C burst)

Here is a zoom of the second burst, which is after a 3.6 msec delay. Here you can see the R/_W bit is set is generate a read request in the chip address byte (0x71).

If your host microcontroller can replicate this activity with a similar delay time, you should (hopefully) be able to read back the ADAU1761 register and memory contents.

-JT