DS90UB964-Q1: REFCLK

Nao

Genius 4905 points

Part Number: DS90UB964-Q1

Hello,

Our customer Surround View system is using TDA3 and DS90UB964.

I have a question about REFCLK for DS90UB964.

CSI-2 of TDA3 is up to 1.5Gbps, so I need to choose 23MHz for REFCLK at DS90UB964?

Regards,

Nao

over 7 years ago

0 Davor Glisic over 7 years ago

TI__Expert 7995 points

Nao,

The DS90UB964 can accept a reference clock ranging from 23 MHz to 25 MHz. If running the CSI-2 transmitter close to the TDA3 max rate of 1.5 Gbps/lane is required, then setting CSI_PLL_CTL=0 and using a 23 MHz reference clock is needed.

Regards,

Davor

0 Nao over 7 years ago in reply to Davor Glisic

Genius 4905 points

Hi, Davor-san

Thank you for your quick reply.

Regards,
Nao

0 Nao over 7 years ago in reply to Nao

Genius 4905 points

Hi, Davor-san

I have one more additional question.

I confirmed DS90UB964-Q1EVMTDA and User's Guide. EVM has a 25MHz OSC.
Do we need to change OSC to 23MHz from 25MHz, when this EVM use with TDA3-EVM?
Let me know any potential problems, when we did not change OSC.

Regards,
Nao

0 Davor Glisic over 7 years ago in reply to Nao

TI__Expert 7995 points

Hi Nao,

Using a 23 MHz oscillator is needed only if you want to set the CSI-2 rate to ~1.5 Gbps / lane. What CSI-2 rate is selected is dependent on the bandwidth needed to pass all the data from the remote sensors. If the bandwidth requirements allow you to use 800 Mbps/lane, you can use 25 MHz reference clock and set CSI_PLL_CTL=10. The TDA3 can operate at lower CSI-2 rates as well.

I suggest you review the following TI design:

Regards,

Davor

0 Nao over 7 years ago in reply to Davor Glisic

Genius 4905 points

Hi, Davor-san

Thank you for your quick reply.
I confirmed TI-Design that you suggesting, but REFCLK is 25MHz...
Does it mean that CSI-2 is running 800Mbps or 400Mbps on this system?
Because TDA3 can not accept 1.6Gbps CSI-2 data rate.

Regards,
Nao

0 Davor Glisic over 7 years ago in reply to Nao

TI__Expert 7995 points

Yes, that is correct.

0 Nao over 7 years ago in reply to Davor Glisic

Genius 4905 points

Hi, Davor-san

Thank you for your quick feedback.

Regards,
Nao

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DS90UB964-Q1: REFCLK