ADAU1701 in selfboot mode and I2C communication
Hi forum,
I have a board with ADAU1701 in standalone mode using an external EEPROM.
The selfboot pin of the ADAU1701 is hardwired pulled-high. In this case according to the datasheet the ADAU1701 will act as the I2C master.
On this board we recently added an MCU and other modules such as digital amplifiers.
Now the MCU is trying to communicate using I2C protocol with the rest of the modules but communication is not possible.
Could it be that the selfboot mode of the ADAU1701 for some reason keeps the I2C bus non-idle for another master to use?
If yes, what is the way around this problem? If let's say, I am not interested in communicating anything between the MCU and the DSP or the EEPROM after initial bootup, will pulling the selfboot pin low free up the I2C bus for my MCU to use and communicate for the amplifier?
the information I am getting from the datasheet is a bit ambiguous.
It is stated that I can still communicate through I2C with the DSP after the DSP bootsup in selfboot mode but at the same time it is stated that in selfboot mode the I2C address pins of the DSP are ignored.
I also found this thread with some relevant information:https://ez.analog.com/message/14301#14301 but I am still not sure what is the easy way around this problem.
Would pulling the selfboot pin low after bootup or possibly cutting off and isolating I2C lines of the DSP and the EEPROM from the rest of the I2C devices help?
thanks
Dimitris
Audio Signal Processors
SigmaDSP Audio Processors
adau1701
Hi Dimitris,
Before I was trying to attempt a connection I2C between aruduino and Eval-ADAU1701 the ADAU1701 was be in Self-Boot and when i clique in the reset they don't work i put a schématic betwen the pin of arduino and pin of card DSP a diode with a resistence (pull-up) try this and tell me
Amine
Hello Dimitris,
The ADAU1701 should only act as a master during the time it is selfbooting and also if it is set to Writeback mode. That is why it was not working in the thread you referenced above. That is an old thread so I will add a new answer to it.
So as long as you do not set it to writeback you can send commands to it and other devices on the buss. So I suppose it would be good to validate what I just said by cutting the traces to the I2C SCL and SDA lines and see if you can communicate with the other devices. You should be able to do it.
There certainly are solutions using I2C bus repeaters but I think you should not have to go that route.
Regarding the address pins. In selfboot mode they are ignored so you cannot set the address of the part. It will be 0x68 and 0x69 regardless of the logic levels at the address pins.
One other question,... Does the DSP complete its booting up? Does the program function? Because is the bootup does not complete then it is conceivable that the I2C bus could be hung waiting for data.
I guess yet another question... Do you have a readback function in your SigmaStudio program like a VU meter? If it were on then it would keep the 1701 in Writeback mode and it would be a master.
Dave T
Hi Dave,
thank you for your fast reply.
regarding your questions:
the DSP should be properly boot up because I have audio coming in and out of it successfully. So I assume that the bootup has been completed.
I do not have any readback function on the DSP design currently.
I will cut the lines and see if this improves things.
Dave, one more thing:
are you aware of the time it usually takes for the ADAU1701 to complete bootup from the external EEPROM?
Is there a way to know when the bootup is complete?
cheers
Dimitris
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