AM625: CSI performance

Conor

Part Number: AM625
Other Parts Discussed in Thread: DS90UB954-Q1

Hi,

We plan to capture multiple camera signals with the CSI2 virtual channel function. Is the virtual channel signal transfer a Linux driver that ensures real-time performance with hard resources such as CSI peripherals and DMA?

Thanks,

Eevee

over 2 years ago

0 Kallikuppa Sreenivasa over 2 years ago

TI__Guru**** 206920 points

Hello Eevee

Thank you for the query.

I am checking internally and will update you.

Please expect delay due to the US holiday.

Regards,

Sreenivasa

+1 Kallikuppa Sreenivasa over 2 years ago in reply to Kallikuppa Sreenivasa

TI__Guru**** 206920 points

Hello Eevee

Please refer below inputs i received from the camera expert.

To have two cameras connected to same instance of CSI using different virtual channels, you would need a deserializer
like the fpdlink (ds90ub960) which would set different VC id for each camera in the CSI packets, all done by hardware.
that can handle 1.6gbps per csi data lane and csi-rx ip on the SoC can route the different Virtual Channels to separate DMA channels.

On AM62x there is a common DMA instance shared with all peripherals. Under DMA stress CSI traffic will not get preferential treatment.I am not
fully sure if that means it can be classified as "Realtime" or not.

Bandwidth guarantees on DMA side are also there on am62a as it has a separate dma instance for csi traffic.

Regards,

Sreenivasa

0 Conor over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 13235 points

Hi, Sreenivasa

Kallikuppa Sreenivasa said:
To have two cameras connected to same instance of CSI using different virtual channels, you would need a deserializer
like the fpdlink (ds90ub960) which would set different VC id for each camera in the CSI packets, all done by hardware.

If only two cameras are connected to AM62x, DS90UB954-Q1 is also a candidate, right?

Kallikuppa Sreenivasa said:
Bandwidth guarantees on DMA side are also there on am62a as it has a separate dma instance for csi traffic.

Are concrete figures provided for the above information?

Thanks,

Eevee

0 Kallikuppa Sreenivasa over 2 years ago in reply to Conor

TI__Guru**** 206920 points

Hello Eevee

Conor said:
If only two cameras are connected to AM62x, DS90UB954-Q1 is also a candidate, right?

Agree.

Conor said:
Bandwidth guarantees on DMA side are also there on am62a as it has a separate dma instance for csi traffic.

Are concrete figures provided for the above information?

This is a generic statement to indicate the difference or 62A advantages with respect to 62x. Currently do not have figures to share. Not sure if we would have these figures any time.

Regards,

Sreenivasa

0 Conor over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 13235 points

Hi, Sreenivasa

I checked AM62A.
As shown in yellow letters below, there was a mention of two connections for the camera. Does this mean the deserializer-based virtual channel solution you're talking about?

https://www.ti.com/product/ja-jp/AM62A3

Thanks,

Eevee

0 Kallikuppa Sreenivasa over 2 years ago in reply to Conor

TI__Guru**** 206920 points

Hello Eevee

Thank you for the inputs.

Again, as i mentioned, this is indicating the capability not the methodology. The interface used could be the above or any other interface depending on the use case.

Ex: Fusion board

https://www.ti.com/tool/TIDA-01413

Regards,

Sreenivasa

0 Conor over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 13235 points

Hi, Eevee

In Application, which uses two cameras, both AM62 and AM62A are options, right? Compared to AM62, AM62A has an ISP and supports DMA dedicated to CSI, is the processing around the camera higher than AM62? I'm wondering which one to consider for applications with two cameras.

Also, is there an upper limit to the number of cameras supported in virtual channel mode?

Thanks,

Eevee

0 Kallikuppa Sreenivasa over 2 years ago in reply to Conor

TI__Guru**** 206920 points

Hello Eevee

Thank you.

If you have option to choose between the 2 devices, 62A would be a better choice.

The choice is very much application dependent and choice of customer.

Regards,

Sreenivasa

0 Conor over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 13235 points

Thanks for the quick reply. I understand.

0 Kallikuppa Sreenivasa over 2 years ago in reply to Conor

TI__Guru**** 206920 points

Hello Eevee

Thank you and have a good day.

Regards,

Sreenivasa

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AM625: CSI performance