DS90UB935-Q1: CSI-2 Errors

Hi,
can you explain your setup? Which SER, DES, Sensor, Cable, how long is the cable?

Hi,

My setup is like this:

We are using boards of ONSEMI to control the serializer and the sensor.

By using python in the devware program we can read out all the registers of the serializer and sensor.

The readout of these registers can you find in the previous post.

Can you please answer the rest of questions?
Which Deserializer are you using? Which cable, how long is the cable?
Can you send reg values from the DES? registers from 0x4C to 0x7D

Used DESER: DS90UB954
There is made use of a 50Ohm Coax RG316 of 3m cable(415-0004-MM250) between the SER and DESER.

Reg values of DESER;

SerialReg 0x4c = 0x1
SerialReg 0x4d = 0x3
SerialReg 0x4e = 0xc
SerialReg 0x4f = 0x64
SerialReg 0x50 = 0x0
SerialReg 0x51 = 0x0
SerialReg 0x52 = 0x0
SerialReg 0x53 = 0x3
SerialReg 0x54 = 0x0
SerialReg 0x55 = 0x0
SerialReg 0x56 = 0x0
SerialReg 0x57 = 0x0
SerialReg 0x58 = 0xde
SerialReg 0x59 = 0x3
SerialReg 0x5a = 0x0
SerialReg 0x5b = 0x32
SerialReg 0x5c = 0x18
SerialReg 0x5d = 0x20
SerialReg 0x5e = 0x20
SerialReg 0x5f = 0x30
SerialReg 0x60 = 0x32
SerialReg 0x61 = 0x0
SerialReg 0x62 = 0x0
SerialReg 0x63 = 0x0
SerialReg 0x64 = 0x0
SerialReg 0x65 = 0x20
SerialReg 0x66 = 0x20
SerialReg 0x67 = 0x30
SerialReg 0x68 = 0x32
SerialReg 0x69 = 0x0
SerialReg 0x6a = 0x0
SerialReg 0x6b = 0x0
SerialReg 0x6c = 0x0
SerialReg 0x6d = 0x7c
SerialReg 0x6e = 0x88
SerialReg 0x6f = 0x88
SerialReg 0x70 = 0x2b
SerialReg 0x71 = 0x2c
SerialReg 0x72 = 0xe4
SerialReg 0x73 = 0x3
SerialReg 0x74 = 0x24
SerialReg 0x75 = 0x7
SerialReg 0x76 = 0x80
SerialReg 0x77 = 0xc5
SerialReg 0x78 = 0x0
SerialReg 0x79 = 0x1
SerialReg 0x7a = 0xf
SerialReg 0x7b = 0xff

May I ask why you want to have a look at the register values of the deser? I want to monitor the MIPI that is used between the sensor and serializer.


Kind regards,
Stijn

Hi Hamzeh,

I already measured the eye-patern of the MIPI signals.
Here were no possible causes found for these errors.

The noise was also measured at the sensor --> Nothing found that could explain this.

Also when streaming the data from the sensor no interruptions/problems are detected.

Are you sure these errors are reported due to errors in the physical layer of the CSI interface?
Could't they be caused by the protocol layers?

Thanks,
Stijn

Stijn,
measuring the Eye diagram means only that your signal quality is good with low jitter, but it does not mean that the content of the signal is okay. The content can be all zeros but the Eye can still look good.

Sure these errors can be also due to protocol layer.

Hi Hamzeh,

Thank you for your clear replay, to give you a better understanding of this behaviour, I also did a read out of the CSI-2 error registers(not only the counter).

They all look like this;

---------- New Error read out ----------

SerialReg 0x5c = 0x8c

SerialReg 0x5d = 0x4

SerialReg 0x5e = 0x0

SerialReg 0x5f = 0x0

SerialReg 0x60 = 0x0

This means that the value 0100 0000 is read out of the  CSI_ERR_STATUS register. This is in the 'reserved' bits of this register. Does this give you some extra information?

Also when looking in the DESER(DS90UB954-Q1) SENSOR_STS_3  register(0x54) there is standing 0x00 while the error counter is in the serializer is counting up? 

Kind regards,
Stijn

Hello Stijn,

the register values you provided tells that the 953 is receiving a signal with RGB checksum errors, which means the video signal content is somehow corrupt.

Please check the followings:

1) sensor settings

2) Sensor - Serializer Interface connections

3) Sensor - Serializer Interface layout : differential pairs, 100 ohm, grounding, layers, Vias...

4) you may have jitter or high skew on the CSI data/ clcok lanes