Clarifying the PSSI Interface of the STM32N657

[Neuraleanus]

I would like to connect a 12-bit ADC operating at 10MSps to the PSSI interface of the STM32N657 device.  There is some confusion as to the nature of the clock source. The reference manual indicates that this may be either an input or an output.  If configured as an output, what is the source of the clock?  Examples suggest that a PWM timer needs to be used.  Here is an illustration of what I would like to do:

Do I need to use the PWM timer as the clock source?

[KDJEM.1]

Hello @Neuraleanus and welcome to the community,

As mentioned in RM0486, the PSSI_PDCK can be configured in input mode (default) or in output mode. When
configured in output mode, the clock is generated by the device RCC.

Also, I recommend you to look at Overall FAQs for PSSI - STMicroelectronics Community, this article provides answers to frequently asked questions regarding Parallel Synchronous Slave Interface (PSSI), listing a known limitation and includes a list of useful resource links.

I hope this answer your request.

Thank you.

Kaouthar

[Neuraleanus]

Ok, assuming that the RCC may be used to configure the PSSI clock, PSSI_PDCK, this is what I see in the clock configuration of STM32Cube:

How does this signal drive the PSSI clock?  MC01 and MC02 have been mentioned, but are grayed-out:

 

How may the RCC be configured to drive the PSSI clock pin?  Is there a tutorial on configuring the RCC?

Does this have anything to do with PSSI_PDCK:

[KDJEM.1]

Hello @Neuraleanus ;

You need to enable the MCO in the Pinout  Configuration.

Then choose the clock source and configure the MCO1 frequency.

Finally, connect PSSI_PDCK pin to MCO pin.

Please look at this How can I output a clock signal to the STM32’s MCO pin? may help you to configure the MCO.

Thank you.

Kaouthar

[Neuraleanus]

Ok, I now have two possible solutions:

1.  Use a PWM timer and wire the PWM output externally to the PSSI_PDCK pin.

2.  Use either MCO1 or MCO2 to drive one of the MCO clock outputs and wire this pin to the PSSI_PDCK pin.

Is there a third option where I drive the PSSI_PDCK internally?

[KDJEM.1 · Accepted solution]

Hello @Neuraleanus ;

No, there isn't. The PSSI_PDCK pin must be connected to a clock source pin like as MCO pin, timer pin… 

You can look at these examples may help you to use PSSI:

• STM32CubeN6/Projects/NUCLEO-N657X0-Q/Examples/PSSI at main · STMicroelectronics/STM32CubeN6 · GitHub
• STM32CubeH7RS/Projects/NUCLEO-H7S3L8/Examples/PSSI at main · STMicroelectronics/STM32CubeH7RS · GitHub

I hope my reply answer your request?

If your request is answered, please click on Accept as Solution on the reply which answered your question.

Thank you.

Kaouthar