AM623: Available CSI2 RX bandwidth

Ryuuichi machida

Part Number: AM623

Hello,

Let me confirm about below.

* According to feature of following datasheet, CSI2 can accept up to 2.5Gbps.(This means up to FHD(1920x1080@60 with YUV16) can be accepted.)

- Support for 1,2,3 or 4 data lane mode up to 2.5Gbps.
(I understand that 625Mbps can be accepted per lane.)

However, on the other hand, there is following description in "7.11.5.3 CSI-2"

- Support for 1,2,3 or 4 data lane mode up to 1.5Gbps.
(I understand that 375Mbps can be accepted per lane.)

It seems that bandwidth which CSI-RX can accept shrink.
Could you please tell me which information is correct ?

BR,

over 2 years ago

0 Kallikuppa Sreenivasa over 2 years ago

TI__Guru**** 197199 points

Hello Ryuuichi, machida,

Thank you for the query.

Ryuuichi machida said:
- Support for 1,2,3 or 4 data lane mode up to 1.5Gbps.
(I understand that 375Mbps can be accepted per lane.)

Please us this information.

Regards,

Sreenivasa

0 Ryuuichi machida over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 12845 points

Hello,

>Please us this information.
Please see page 134 of following datasheet.
https://www.ti.com/lit/ds/symlink/am623.pdf

BR,

0 Kallikuppa Sreenivasa over 2 years ago in reply to Ryuuichi machida

TI__Guru**** 197199 points

Hello Ryuuichi, machida,

Thanks, looks fine. Please refer to the page that you have pointed.

Regards,

Sreenivasa

0 Ryuuichi machida over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 12845 points

Hello,

>Please refer to the page that you have pointed.
Did you mean that 1.5Gbps is correct information ?

BR,

0 Kallikuppa Sreenivasa over 2 years ago in reply to Ryuuichi machida

TI__Guru**** 197199 points

Hello Ryuuichi, machida,

Thank you and your understanding is correct.

Regards,

Sreenivasa

0 Ryuuichi machida over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 12845 points

Hello,

Understood.(So user can not use 1920x1080@60p w/ 16bit data..)
Please fix "feature" section of datahseet.(Please submit it to documentation team.)

BR,

0 Kallikuppa Sreenivasa over 2 years ago in reply to Ryuuichi machida

TI__Guru**** 197199 points

Hello Ryuuichi, machida,

Thank you for the input and noted.

Regards,

Sreenivasa

0 Ryuuichi machida over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 12845 points

Hello,

Sorry for asking you again. I found following thread.
However, according to following thread, it seems that 2.5Gbps means "per lane".
(1) AM625: processor camera capabilities - Processors forum - Processors - TI E2E support forums

If above sentence mean "per lane", total available bandwidth will change.
Could you please confirm about this ?

BR,

0 Kallikuppa Sreenivasa over 2 years ago in reply to Ryuuichi machida

TI__Guru**** 197199 points

Hello Ryuuichi, machida,

Thank you for the query.

The 1.5G data rate is per lane. (Serial, differential interface)

Regards,

Sreenivasa

0 Ryuuichi machida over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 12845 points

Hello,

>The 1.5G data rate is per lane. (Serial, differential interface)

Umm, URL which I attached said TI use OV5640 to evaluate camera input.
https://cdn.sparkfun.com/datasheets/Sensors/LightImaging/OV5640_datasheet.pdf

According to above URL, this camera have 5M pixel.
And also, this supports following dataformat.
* support for output formats: RAW RGB, RGB565/555/444, CCIR656, YUV422/420, YCbCr422, and compression

So, worst case is 5Mpixel @ 60 with 16bit data.
As a result of formula 5Gbps(2592x1944x60x16 = 4837Mbps = 5Gbps) is required.
And, this camera have only two CSI lane. So, 2.5Gbps is required per lane.

As a result of above, if TI evaluate CSI input by using OV5640, it seems "2.5Gbps data rate is per lane" is correct information.

Could you please re-confirm ?

BR,

0 Kallikuppa Sreenivasa over 2 years ago in reply to Ryuuichi machida

TI__Guru**** 197199 points

Hello Ryuuichi, machida,

Thank you for the inputs.

Based on the validation results, the data rate has been updated to 1.5G per lane.

Regards,

Sreenivasa

0 Ryuuichi machida over 2 years ago in reply to Kallikuppa Sreenivasa

Guru 12845 points

Hello,

OK, I understood. (So totally, this device supports up to 6Gbps (1.5Gpbs x 4))
Do you have plan to release CSI DC/AC spec in datasheet ?
Since there is no information about CSI electrical spec, so I would like to confirm when you will release this spec.
(If you release CSI_CLK sepc, I can understand about this more easily.)

BR,

0 Kallikuppa Sreenivasa over 2 years ago in reply to Ryuuichi machida

TI__Guru**** 197199 points

Hello Ryuuichi, machida,

Thank you for the suggestion. I will provide your feedback to the team.

For standard interfaces, my understanding is that it is expected that the referenced standards will referred for the specs.

Regards,

Sreenivasa