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External Delay with ADAU1466

I have connected IS62WVS5128GBLL - 4MBit SRAM to ADAU1466. It used for block ExtDelay. Slave is 5, SPI Mode 3. It works well (only) with 13,5MHz. RAM size 524288 bytes.

I have connected ExtDelay to channel 0 and channel 1. It works well, in both chgannels I can use delay with more than 2 sec.

My question is - is possible to use more memories for other channels?

How maximum number of ExtDelay can be used in SigmaStudio 4.5 ? Which is principle of memory sharing/settings between ExtDelay blocks?

  • Can you explain how you connect this ram chip to adau? Slight smile

  • Hello Efremoff,

    You connect it the same way the EEPROM is connected on the evaluation board. So look at that schematic. If you also will have an EEPROM and will be selfbooting then you need to connect the Slave Select pin to one of the MP pins on the DSP and then setup the External SPI delay cell to use that Slave Select when sending data to the RAM. 

    Hello Andrej,

    Sorry we did not reply to your message. We are still working on an update to the EXT RAM block. This block can be grown to more channels but the issue is bandwidth on the SPI bus. There is a limitation as to how fast it can be operated and then there are PCB layout issues that can cause data errors. So growing the block to add more channels will be limited by the SPI speed and the sampling rate. Once this new block is complete and tested we will be working on a better characterization of how many channels vs sampling rate vs SPI rate so give users a better idea of capabilities. Hopefully this will happen in the next couple of months. 

    Dave T

  • Dave, thanks for answer.

    I already find schematic for connection SRAM to adau and info in wiki about external delay. For now i try to find - which chips with 32-64Mb ram size will be work correct. For now i find only Pseudo SRAM chips, like ESP PSRAM64H. Generally PSRAM little bit slower then SRAM. What your opinion about PSRAM uses?

    What memory IC you can recommend with with size 32-64Mb (4-8MB).

    Regards.