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Observer alen89
Observer
200 Views
Registered: ‎06-26-2019

QSPI Multiplexed access

Dear,

Due to have redundancy on the board I use 2 qspi memories multiplexing the chip select. The problem that I have is when you boot from one memory, only this memory is in QSPI mode and unlocked. So my question is, someone know if it is possible to write qspi commands from user space just to configure the secundary memory in this mode?. 

I use QSPI in single mode. The memories are n25qu256.

Thank you in advance,

Alen.

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5 Replies
191 Views
Registered: ‎07-23-2019

Re: QSPI Multiplexed access

 

If I'm not wrong, QSPI chips start at a default 1x and there is a command to swap to 4x.

When you say:

"when you boot from one memory, only this memory is in QSPI mode and unlocked"

I think that's not right, it's the configuration engine what tells the memory to change to QSPI mode

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Observer alen89
Observer
168 Views
Registered: ‎06-26-2019

Re: QSPI Multiplexed access

And it is possible to do it from user space?
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157 Views
Registered: ‎07-23-2019

Re: QSPI Multiplexed access

I believe so, otherwise who does it?

I just had a look at micron's N25Q256 (should be compatible with other brands). There is a command list that shows:

err1.png

And there are other read and write commands in dual and quad as well.

also, in the SDK libraries, I would expect such functions in the libraries provided for SPI

 

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Observer alen89
Observer
131 Views
Registered: ‎06-26-2019

Re: QSPI Multiplexed access

Well for inspection spi-zynqmp-gqspi does not and spi-nor.c also not, only found in mtdchar.c for the mtd-utils...
So probably I need to patch a driver..
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87 Views
Registered: ‎07-23-2019

Re: QSPI Multiplexed access

Strange... I have used PCAP to read/write the config SPI memory and I assume it uses quad SPI without any user intervention. I wonder if you could use that as well

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