AM623: SPI timing requirement

Hello austin.chen

Thank you for the query.

The slew rate that you mentioned is for the input of the SoC.

You will have to verify the output slew rate using the IBIS model.

Could you please elaborate your query.

Regards,

Sreenivasa

Hi, Sreenivasa

My problem is the actual signal to CPU input that can't rise fast enough to meet CPU input SPEC.

I think the CPU input SPEC is defined under clock is 50MHz.

I expect that the slew rate SPEC can be slower with 25MHz SPI clock.

Hello austin.chen

Thank you for clarifying.

As i understand, irrespective of the operating frequency , the input slew rate requirements are required to be considered.

Can you confirm if the values you have in the above table is what you are seeing by measurement or by simulation?

Regards,

Sreenivasa

Hi, Sreenivasa

The value is measured on our PCBA.

Since CPU is input, the signal rising/falling is controlled by device.

Unfortunatedly, the output driving strength can't be fine tuned on device side.

There is no output rising/falling data in device datasheet.

But there is input AC characteristic for your reference

Hello austin.chen

Thank you for clarifying.

Could you please share the captured waveform picture.

regards,

Sreenivasa

Hi, Sreenivasa

Please reference the waveform below

Falling

Rising

Hello austin.chen

Thank you for the inputs.

Let me check with the device expert and update you.

Regards,

Sreenivasa

Dear Sreenivasa

Do you have any update about this question?

Hello austin.chen

Thank you for following.

I do not have any update from the device expert.

The recommendation was to follow the data sheet irrespective of the speed configuration.

I need to consult the timing expert. Please expect some delay.

Regards,

Sreenivasa

Hi Sceenivasa

Do you have any update about this question?

Hello austin.chen

Thank you for following.

I do not have any update from the device expert.

We had a similar requirement for I2C and we are using an RC in the AM64x.

You could reference the AM64x EVM to have a look.

Do you see that being an option in the custom hardware you have?

Regards,

Sreenivasa