ADAU1452 maximum self-boot image size, and sharing EEPROM
Hello,
I'm having some trouble determining the worst-case self-boot image size which could be possibly generated by SigmaStudio for the ADAU1452. If I add up the total size of DM0, DM1 and program space available in the 1452, I end up with 192 KiB of memory.
However, on the ADAU1452 dev kit, there's a 1 MBit (=128 KiB) EEPROM. I am thinking this could be either due to:
The dev kit just doesn't support self-booting any program size;
DM0 and DM1 will be never fully occupied in a self-boot image, because not all of it needs initialization (this seems the most logical reason to me).
I can't seem to find any minimum memory requirements for self-boot in the ADAU1452 documentation. Can I safely assume that putting a 1 MBit EEPROM on my custom design will always be sufficient for self-boot in the future? Maybe the maximum self-boot image ever produced is even less?
The EEPROM will be mainly used for my MCU to store some settings, and to provide swap space for the MCU's OTA firmware update process.
Right now, the internal flash of the MCU is big enough to have the DSP code embedded in the program and I use SigmaStudio's auto-generated download code to boot the DSP via SPI. However, I want to be prepared for future increase of both the MCU and DSP program and make my design self-boot ready. I'm aware that I will be having 2 SPI masters connected to the same EEPROM this way, and that I need to take care of this during my boot and upgrade processes. I think that I can solve this by having control over the reset line of the DSP from my MCU.
I need to know what size EEPROM to select to accommodate for all of this.
Audio Signal Processors
adau1452
eeprom
adau145x
SigmaDSP Audio Processors
selfboot
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Hello danielschenk,
Yes, we did not put the largest size EEPROM on the eval board because it is not likely to be an issue when evaluating the part.
The I2C description of the Selfboot section of the datasheet has the best hint for the max size:
The slave EEPROM has 16-bit addressing, giving it a size of between 16 kb and 512 kb.
So the 512 kb EEPROM size will be the largest you will need. The SPI EEPROM and flash come in much larger sizes so you can easily use the upper part of the memory without stepping on the selfboot program.
You are correct to understand that the two masters are an issue with SPI. Yes, you can hold the DSP in reset but make certain that the controller's pins are tri-stating when you release the reset. You probably will just switch it over to the slave port at that point so you can control the DSP once it is booted, unless your controller has more than one comms port.
Dave T
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