DS90UB960-Q1: What is the minimum frequency that the Framesync generator can produce?

kanna

Part Number: DS90UB960-Q1
Other Parts Discussed in Thread: DS90UB953-Q1

Tool/software:

Hi,

We are using the DS90UB960-Q1 deserializer and DS90UB953-Q1 serializer to transfer the MIPI data. We need to generate a 10 Hz FrameSync signal with a 10% duty cycle from the deserializer.

We referred to the deserializer datasheet for FrameSync generation.

Calculation for the 10 Hz frequency: (1 sec / 10 Hz) / 600 ns - total count - approximately 166,667.

For a 10% duty cycle, the high time is 16,666, and the low time is 150,000.

Is it possible to generate 10 Hz at a 10% duty cycle?

over 1 year ago

0 Thomas Bejin over 1 year ago

TI__Mastermind 28401 points

Hi Kanna,

Thanks for your question. In this case, we would need to enable frame sync in register 0x18 with low/high time mode. The frame sync high time here would be 10ms, and FS low time would be 90ms. When operating with the 953 the typical BC rate would be 50-Mbps back-channel operation, the frame period is 600 ns (30 bits × 20 ns/bit).

To get a frame sync high time of 10ms, set high time register to 0x411A (high / low register). However for the frame sync low time, we wouldn't be able to set to the FS low time to 90ms. Do you know if we'd be able to set the BC rate to a different here? For example, if the resolution of the sensor is low enough, we could set the BC rate to 25Mbps rather than 50Mbps and reduce the FPD-Link forward channel rate as well.

Best,

Thomas

0 kanna over 1 year ago in reply to Thomas Bejin

Intellectual 365 points

Hi Thomas,

We have referred to the DS90UB960-Q1 deserializer datasheet for configuring the BC frequency. According to the register settings, we found that the BCC_CONFIG register (Address = 0x58) have only three frequency ranges: 2.5 Mbps, 10 Mbps, and 50 Mbps.

Is it possible to set 25 Mbps?

0 Thomas Bejin over 1 year ago in reply to kanna

TI__Mastermind 28401 points

Hi Kanna,

Is Ub960 needed for the end application? BC frequency would need to be set to 25Mbps matching below:

Best,

Thomas

0 kanna over 1 year ago in reply to Thomas Bejin

Intellectual 365 points

Hi Thomas,

I have referred to the TI datasheet from the website below. The datasheet mentions only three frequency ranges for the BC_FREQ_SELECT setting.

DS90UB960-Q1 datasheet - https://www.ti.com/product/DS90UB960-Q1

Currently, we are using a 4 Gbps MIPI CSI-2 for the forward channel for a 2.3MP @27FPS camera module.

Is there any other way to generate the FrameSync signal?

0 Thomas Bejin over 1 year ago in reply to kanna

TI__Mastermind 28401 points

Hi Kanna,

In this case why would frame sync be 10Hz if FPS is 27? One other option would be for SOC to generate frame sync & pass to des.

Best,

Thomas

0 kanna over 1 year ago in reply to Thomas Bejin

Intellectual 365 points

Hi Thomas,

We plan to use a maximum frame rate of 27 FPS and a minimum of 10 FPS. Additionally, external trigger support is not available.

If we set the BC to 10 Mbps, will it reduce the forward channel speed? Additionally, we noticed that BC at 10 Mbps operates in Non-Synchronous mode. Will this affect the forward data?

+1 Thomas Bejin over 1 year ago in reply to kanna

TI__Mastermind 28401 points

Hi Kanna,

Yes, in 10Mbps BC rate we would need to use async mode with either serializer internal clock or external clock provided to the ser.

Best,

Thomas

0 kanna over 1 year ago in reply to Thomas Bejin

Intellectual 365 points

Hi Thomas,

Will it reduce the MIPI CSI speed?

+1 Thomas Bejin over 1 year ago in reply to kanna

TI__Mastermind 28401 points

Hi Kana,

For non-sync internal clock and non-sync external clock CSI bandwidth does not need to be reduced unless the UB935 is used in half rate mode.

Best,

Thomas

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DS90UB960-Q1: What is the minimum frequency that the Framesync generator can produce?