ADAU1467 self boot EEPROM issues

Hello Julien,

I have not downloaded your program but I can see what is happening most likely.

Growing an FIR filter uses the same coefficients, using two separate cells will use two sets of coefficients so it takes twice the storage space.

If the file is too large for the EEPROM then it will wrap about and start writing at the start of the EERPOM overwriting the start of the file. So when the DSP starts loading it reads the first byte and if it is not an 0xAA then it stops since the contents are not valid.

So either you need to use a larger EEPROM or go back to the stereo version of the FIR filter.

Dave T

Hello Dave,

Many thanks for your answer.

Unfortunately (for me) you are right.... I don't know why, I put one 256k EEPROM instead of 1M like the Eval board...

1M EEPROM is the maximum needed by the ADAU1467 ?

One more time, many thanks !

Dave,

I have changed the 256kb by a 1Mb EEPROM (AT24CM01). It's working fine now !

But I have a doubt about the configuration of the EEPROM, according to me we need 3 bytes to adress 1Mb, but If I configure that in the window "EEPROM Properties" it's not working (it's like before, with the 256kb EEPROM).

If I configure 2 bytes, It's working fine, but I think, like that, I can use only 512kb, am I right ?

Best regards.

Julien

Hello Julien,

This is an I2C EEPROM so it will only accept a two-byte address for the data location. How the I2C standard gets around this limitation for larger memories is to add a 17th bit (A16) into the I2C device address byte. This means that the bit needs to be separated and transmitted separately (well, in a different byte but the same message) then reassembled upon being received. The Comms port in the DSP is not designed to do this so we cannot support I2C EEPROMs larger than 512k. With SPI EEPROMs we can use 24 bit addressing so it is not a problem with those.

I have not heard of anyone filing up a 512k EEPROM using a Sigma300 (ADAU1452) but the 1467 can hold a lot more memory but the max program size is still the same for both generations of parts. It would take more study on my part but it might be possible to fill up an I2C EEPROM on the Sigma350.

I got this from page 47 of the datasheet:

Considerations When Using a 1 Mb I2C Self Boot EEPROM
Because of the way I2C addressing works, 1 Mb of I2C EEPROM
memory can be divided, with a portion of its address space at Chip Address 0x50; another portion of the memory can be located
at a different address (for example, Chip Address 0x51). The
memory allocation varies, depending on the EEPROM design. When the EEPROM memory is divided, the memory portion that resides at a different chip address must be handled as though it
exists in a separate EEPROM.

So this shows that you can use this extra memory for other user functions but not for selfboot.

The datasheet does not really go into a discussion of program size and hex file sizes. I suspect that you will not run into issues.

Dave T

Hello Dave,

Thanks for your explanations, it's now clear for me.

I did some tests, I also think 512K is enough for my application.

Next time I will use a SPI EEPROM, just in case !

Best regards,

Julien