AM6442: Is it possible to connect 4 devices to OSPI using 4 CSs ?

Hello Hideaki

Thank you for the query.

Hideaki Matsumoto said:

Again, is it possible to connect two devices using two CSs to OSPI ?

Please refer below threads for assessment on using multiple devices on the QSPI interface. This is not a use case that has been tested and this is not recommended due to challenges with routing and signal integrity.

(16) AM6442: OSPI trace routing while connecting onto two devices - Processors forum - Processors - TI E2E support forums

(+) AM62x: OSPI Flash Question - Processors - INTERNAL forum - Processors - INTERNAL - TI E2E support forums

(+) AM6412: OSPI with 2 Devices - Processors forum - Processors - TI E2E support forums

Regards,

Sreenivasa

Hi Sreenivasa,

Thank you for your reply, but let me confirm again. AM64x supports multiple devices on the QSPI interface as its specification, but we don' recommend it ?

Is this bug or errata ?

Regards,
Hideaki

Hello Hideaki

Thank you for the inputs.

Hideaki Matsumoto said:

let me confirm again. AM64x supports multiple devices on the QSPI interface as its specification, but we don' recommend it ?

Your understanding is correct.

Is this bug or errata ?

The recommendation is due to the implementation challenges including performance and signal integrity.

Regards,

Sreenivasa

Hi Sreenivasa,

Thank you for your answer and recommendation.

The customer has already recognized and agree with you about the implementation challenges including performance and signal integrity, but they would like to go ahead for designing the multiple devices onto OSPI.

Therefore, they’re now checking the design by board simulation, and will summarize issues regarding signal integrity.

For now, their concern is how to configure it with software

Could you tell them how they can configure with SysConfig when multiple devices put onto OSPI ?

Or tell them alternative way if it cannot be configured with SysConfig.

Regards,

Hideaki

Hello Hideaki

Thank you for the inputs.

Let me check internally and update you.

Regards,

Sreenivasa

Hi Sreenivasa,

Did you get any update ? We need an answer or any advice, because the customer's design needs to be fixed soon.

Thanks and regards,
Hideaki

Hello Hideaki

Thank you for follow-up.

I have reached out to the expert and will update you when i have some inputs.

Regards,

Sreenivasa

Hello Hideaki

Thank you for the note. Will do the needful.

Regards,

Sreenivasa

Hello Hideaki

Here are some inputs i received from the design team.

The current OSPI implementation assumes use of one device and the device can be connected to any of the chip select.

This is in line with our recommendation to connect only one device.

If customer is looking to implement, they will have to select one of the chip select at a given time and do the same for all the chip selects.

Updates to the code has to made to merge the initialization and selection of the CSn bit.

Refer below for the register information

Regards,

Sreenivasa