Use selfboot EEPROM also for µC?

ChristianH Question

Jan 5, 2012 00:00

Hi,

my plan is the following application:

An ADAU1702 boots itself over I2C from an EEPROM.

A µC is managing a LCD and a pushbutton for preset recall i.e. either changing some EQ coefficients or selecting a filter in an "IdxSelectable Indp. Multiple Band Filter". That should be possible after the 1702 has finished booting from the EEPROM (no writeback planned).

The preset names and other stuff to be displayed on the LCD via the µC should be stored in the same EEPROM that is used by the 1702 for selfboot.

There will also be a variant without µC and LCD (PCB assembly option) so I do not want to use the µC for booting the ADAU.

2 questions:

- How to check wether the 1702 has finished booting? Maybe placing a DC block in the schematic that sets a GPIO to 1..??

- Can additional data be stored into the EEPROM used for selfboot? If yes, what do I have to care for?

Thanks

Christian

Audio Signal Processors

adau1702

i2c

eeprom

SigmaDSP Audio Processors

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ADIApproved Reply

Jan 6, 2012 00:00

Hi Christian,

You can check that selfboot is complete as you describe by setting a GPIO pin high using a DC source set to 1. You can store additional information in the self boot EEPROM as long as you don't put the info in the address space that is being used by the 1702 self booter. The max memory size required by the 1702 for self boot is 6688 bytes. You could place the additional info at a higher EEPROM address.

Best Rgds,

Alan

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ChristianH Reply

Jan 9, 2012 00:00

Hi Alan,

thank you, we will try that.

Regards

Christian

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ADIApproved Reply

Jan 15, 2012 00:00

Christian,

You can check to see how big the self-boot data is by following method 2 in this tutorial: https://ez.analog.com/message/5759#5759

Open the resulting hex file in a hex editor (we use Ultraedit) and you should be able to figure out how many bytes are required to store the image in the EEPROM.

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