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Selfboot + writeback + I2C commands

Question asked by rugastro on Oct 12, 2010
Latest reply on Jun 4, 2015 by DaveThib

I'm using an ADAU1701 in selfboot mode, using my uc to emulate the boot EEPROM.

At the end of selfboot sequence I add the multple writeback command (0x04) and I recall writeback every 100ms to read values from my DSP.

Between a writeback and next one I want to send command to my DSP, such as mute and routing commands, so I must send as master commands to ADAU1701.

So, I start in selfboot mode and I use writeback, but I also send command as in I2C mode (being careful that I'm not writing as master during selfboot and writeback).

 

Datasheet said:

 

"After the ADAU1701 finishes self-booting, additional messages can be sent to the ADAU1701 on the I2C bus, although this typically is not necessary in a self-booting application. The I2C device address is 0x68 for a write and 0x69 for a read in this mode."

 

So, it's possible to write and read by I2C as master. Then:

 

"The ADAU1701 is a master on the I2C bus during self-boot and writeback. Although it is uncommon for an application using self-boot to also have a microcontroller connected to the control lines, care should be taken that no other device tries to write to the I2C bus during self-boot or writeback."

 

I have respected also these conditions, but commands don't work.

Have I to do something else, like to set low SELFBOOT pin? Are there some special procedure to become a master starting in SB mode?

 

Thank you

 

Stefano Rossi

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