DS90UB954-Q1: Is RX_FREQ the same as FPD3_MODE frequency?

Ann_Lien

Genius 16210 points

Part Number: DS90UB954-Q1

Hello expert,

We are trying to dump some register value from TI-954 and found one issue below:

PORT_CONFIG Register(Address 0x6D)

We configure “PORT_CONFIG Register” as “0x7e”.

So, “FPD3_MODE” should be “10: RAW12 Mode / 75 MHz”.

But, we read the following 2 Register:

RX_FREQ_HIGH (Address 0x4F) = 0x25 (37)
RX_FREQ_LOW (Address 0x50) = 0x00

We have no idea whether the value of “RX_FREQ” should be the same with “FPD3_MODE (i.e. 75MHz)” ? Could you help us to verify ? Many thanks.

Best regards,

Ann Lien

over 6 years ago

0 Casey McCrea over 6 years ago

TI__Guru** 103215 points

Hello Ann,

FPD_MODE is corresponding to the maximum PCLK in the mode (75MHz in this case). But the RX_FREQ is the actual frequency used by the serializer depending on the video sensor output

Best Regards,

Casey

0 Ann_Lien over 6 years ago in reply to Casey McCrea

TI__Genius 16210 points

Hello Casey,

Thanks for your reply. So these two value would not be always the same, right? Thanks a lot!!

Best regards,

Ann Lien

0 Casey McCrea over 6 years ago in reply to Ann_Lien

TI__Guru** 103215 points

Hello Ann,

They can be the same, but it depends on the PCLK used in the application. They don't need to be the same

Best Regards,

Casey

0 TC Chou over 6 years ago in reply to Casey McCrea

Prodigy 210 points

Hello Casey,

I am the original questioner, TC.

Currently, our Sensor's PCLK is 72 MHz and “FPD3_MODE” is configured as “RAW12 Mode / 75 MHz”.

After reading register value, RX_FREQ_HIGH (Address 0x4F) is "0x2f" and RX_FREQ_LOW (Address 0x50) is 0x00.

We wan to know whether it is correct ? Thanks.

Sincerely,

TC.Chou

0 Casey McCrea over 6 years ago in reply to TC Chou

TI__Guru** 103215 points

Hello TC,

Yes this is correct. For RAW12 HF mode see the serializer datasheet for how to calculate the FPD-Link line rate:

LineRate = PCLK*(2/3)*28 = 1.344Gbps

913A/933 serializers use a 28 bit frame size for the forward channel, so the FPD-Link frame frequency is LineRate/28

LineRate/28 = 48MHz

0x2F = 47(dec) which is approx = 48MHz

Best Regards,

Casey

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DS90UB954-Q1: Is RX_FREQ the same as FPD3_MODE frequency?