topic Re: MIPI-CSI2 Required Operating Frequency Calculation in i.MX Processors

MIPI-CSI2 Required Operating Frequency Calculation

ko-hey — Mon, 07 Sep 2015 10:14:23 GMT

Hi all

I want to know that the i.MX6D can be received 3MP at 60fps with MIPI-CSI2.

In connection with the above, I have question about how to calculate MIPI-CSI2 required operating frequency.

The maximum bandwidth in MIPI-CSI2 4lane is 3,200Mbps (= 800Mbps/lane x 4lane).

Addition for this, there are following examples in RM(Rev3.0).

To be calculated from the example, I think it is overflowed.

The calculation result is below.

6Mpixel x 24bit x 15fps x 1.5cycles/pixel = 3,24Mbps

Does my calculation is wrong ?

Please tell me how to calculate.

Also please tell me how to calculate the required operating frequency.

Add info:

I posted the following question before but no one answered.

How to calculate MIPI CSI-2 required operating frequency

Ko-hey

Re: MIPI-CSI2 Required Operating Frequency Calculation

igorpadykov — Mon, 07 Sep 2015 11:50:04 GMT

Hi Ko-hey

assuming 125 MByte/s per lane, with configuration:

6Mpixel x 24bit x 15fps x 1.5cycles/pixel = 270MB/s * 1.5= 405MB/s

bandwidth will be insufficient.

Best regards

igor

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Re: MIPI-CSI2 Required Operating Frequency Calculation

ko-hey — Tue, 08 Sep 2015 10:08:14 GMT

Hi Igor

For 4 lane configuration, the maximum bandwidth is 400MB/s.

So i.MX6D can't support the settings (6Mpixel x 24bit x 15fps x 1.5cycles/pixel ).

Is it correct ?

The example is wrong, isn't it ?

Once again I say, I want to know that the i.MX6D can be received 3MP at 60fps with MIPI-CSI2.

And there data format is RAW Bayer 12bit.

From above, I need following bandwidth.

Is it correct ?

3Mpixel x 12bit x 60fps x 1 cycles/pixel = 270MB/s x 1 = 270MB/s

As a result, can i.MX6D support the spec ?

ko-hey

Re: MIPI-CSI2 Required Operating Frequency Calculation

igorpadykov — Tue, 08 Sep 2015 11:02:57 GMT

Hi Ko-hey

yes for 1 cycles/pixel calculation bandwidth is correct :

3Mpixel x 12bit x 60fps x 1 cycles/pixel = 270MB/s x 1 = 270MB/s

it can be supported with 3,4 lanes configuration.

Best regards

igor

Re: MIPI-CSI2 Required Operating Frequency Calculation

ko-hey — Thu, 10 Sep 2015 01:31:42 GMT

Hi Igor

According to your answer of another thread, generic data needs two cycles in MIPI-CSI2 interface.

https://community.freescale.com/thread/373387

As a result, the required data volume is below when I use generic data with MIPI-CSI2 interface.

Is it correct ?

3Mpixel x 12bit x 60fps x 2 cycles/pixel = 270MB/s x 2 = 540MB/s

If above calculation is correct, since the bandwidth is insufficient, i.MX6D can't support my customer's requirement.

Is it correct ?

Ko-hey

Re: MIPI-CSI2 Required Operating Frequency Calculation

igorpadykov — Thu, 10 Sep 2015 01:48:16 GMT

Hi Ko-hey

you are right: for MIPI-CSI2 generic data needs two cycles, so

it will be 405MB/s and bandwidth is insufficient.

Best regards

igor

Re: MIPI-CSI2 Required Operating Frequency Calculation

ko-hey — Thu, 10 Sep 2015 01:51:16 GMT

Hi Igor

Thanks !

Ko-hey