TDES960: About CSI-2 Transmitter Frequency setting

takahiro higuchi

Part Number: TDES960

Hi Support Team

According to 7.4.19 CSI-2 Transmitter Frequency, it is stated that the CSI-2 timing parameters are automatically set when CSI-2 TX Data Rate=800Mbps and 1.6Gbps are set.
I believe that the CSI-2 timing parameters are automatically set under the following conditions, is this correct?
REFCLK=23MHz, CSI_PLL_CTL[1:0]=10, CSI-2 TX Data Rate=736Mbps
REFCLK=26MHz, CSI_PLL_CTL[1:0]=10, CSI-2 TX Data Rate=832Mbps

The above conditions were not listed in Table 7-14.

Best regards.

over 1 year ago

0 Thomas Bejin over 1 year ago

TI__Mastermind 19521 points

Hi Higuchi-san,

Thanks for reaching out with this question. You are correct that CSI transmitter rate will depend on the reference clock used. For your application, what is the reference clock which is used for the TDES960?

Best,

Thomas

0 takahiro higuchi over 1 year ago in reply to Thomas Bejin

Prodigy 150 points

Hi Support Team,

Thank you for your response.

We are considering a reference clock of 23 or 26 MHz for the TDES960.

Best regards,

0 Logan Cummins over 1 year ago in reply to takahiro higuchi

TI__Guru 63020 points

Hello,

Since today is a US public holiday, we will resume activity on this thread tomorrow. Thanks for your patience.

Regards,

Logan

+1 Casey McCrea over 1 year ago in reply to Logan Cummins

TI__Guru** 103215 points

Takahiro,

You are correct that the CSI-2 rates will scale as you mentioned with the REFCLK frequency and there is no need to program any CSI-2 timing parameters. Those will be automatically set for the supported rates across the allowable REFCLK frequency tolerance.

Best Regards,

Casey

0 takahiro higuchi over 1 year ago in reply to Casey McCrea

Prodigy 150 points

Hi Support Team,

Thank you for your response.

Am I correct in understanding that the timing parameters for CSI-2 need to be adjusted only at 400Mbps, and that the timing parameters are automatically set at 800Mbps and 1600Mbps as long as the REFCLK frequency is within the acceptable range?

Best regards,

+1 Thomas Bejin over 1 year ago in reply to takahiro higuchi

TI__Mastermind 19521 points

Hi Higuchi-san,

Thanks for your follow up. Going back to your original question for 800Mbps rate, this is described in the table below for the 25MHz REF_CLK frequency.

When a 23MHz or 26MHz oscillator are used, the CSI-2 TX data rate will scale accordingly. In this case, we would see the data rates you referenced in the original post, with 736Mbps for 23MHz reference clock, and 832Mbps for 26MHz reference clock.

Please let me know if you have any additional questions here!

Best,

Thomas

Because of the holidays, TI E2E™ design support forum responses will be delayed from Dec. 25 through Jan. 2. Thank you for your patience.

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TDES960: About CSI-2 Transmitter Frequency setting