[STM32U545] OSPI write only

Hi @KDJEM.1  Thank you for your quick answer.

The only thing I can say about the use case is that I don't use any kind of memory, I have a NUCLEO-U545REQ and I need to drive at high speed rate 4 I/O (or 8 I/O) at the same time.

I need to have a clock at 40MHz, and the other I/O at the same speed or faster.

I though the OSPI was the best option to do that but the problem is I need to use the QSPI (or OSPI) as a custom parallel serializer, and for that I need to use a send only system, with no opcode of anykind, only data.

Thank you,

Loïc

Hello, @KDJEM.1 .

I tried to do what you say but nothing is working.

In my environnement, I've remove all the autopolling and other thing that makes a read operation to only make a write with DMA.

It is running but nothing comes out at the clock...

I've look to PSSI, it is very interesting because it is almost what I need. The PSSI can send and receive data at high speed but it needs a clock input, and in my application I need to have a clock output. Do you have any other possibilities ?

BR,

Loïc

@KDJEM.1 

Yes I only send data phase, without instruction phase, address phase, alternate-byte phase, dummy-cycle phase.

I would like to skip every phase to send only the data and don't disturb the chip that will receive the data.

The chip select signal don't change level, it is only 1 or 0.

Can the PSSI work without a PSSI_PDCK signal input from an external device ? Only with the pssi_hclk (AHB clock) in the STM32U545.

Thank you,

Loïc

Hello @KDJEM.1 ,

->You cannot send only data phase.

What about if I use the OCTOSPI_CCR.SIOO register to 1, can it make the instruction to be send only at the start of the application with the first send frame and after skip the instruction phase ?

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->No, please look at Overall FAQs for PSSI - STMicroelectronics Community

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Maybe with an RCC it will work don't you think ?

Thank you,

Loïc