Hi,
We are using UB953-954 Ser-Deser pair for connecting to Image sensor IMX390 in our product.
Here we are able to configure the Ser-Deser and Sensor to the desired configuration with I2C operations.
However, the CSI-clock output of deserializer does not match the csi-clock input of Serializer.
Scope readings attached.
The CSI clock as we understand should produce
a) High frequency (~300MHz) signal with ~200mV amplitude duting data transfer period
b) LP11 i.e both P and N pins should be ~1V in frame blanking period. (and thus at the rate of ~60Hz for 50 FPS video.)
As we can see in the attached images, the serializer input CSI clock follows this exect pattern.
However, the Deserializer output CSI clock seems to be deviating in 2 aspects.
a) Amplitude of high frequency signal during data transfer period. (getting only 20~30 mV instead of 200mV)
b) Frequency of LP11 Occurence (observing LP11 State at a rate of 60KHz instead of ~60 Hz)
Note on Images Attached:
csi_clk_voltage_levels.png : csi clk cam -> ser input , csi clk main -> deser output
ser_in_csi_clk.png : Serializer output clock becoming LP11 at ~52 Hz for 60 FPS.
deser_out_csi_clk.jpg : Deserializer output clock becoming LP11 at ~62 KHz for 60 FPS.
We are running our ser-deser in CSI-2 Synchronous mode, with non-continuous Clock, configuring the sensor to produce 1920x1080 frames at 60FPS
Also, to isolate the issue we tried the pattern generator code as given in UB954 specification, and did not configure serializer.
The same CSI clock behaviour could be seen with pattern generator configuration as well.
Ser-Deser Configuration is as follows:
Deser : {Reg Address, Reg Value}
{0x4c, 0x01},
{0x33, 0x01}, // 4Lane, non-continuous Clock
{0x20, 0x20},
{0x42, 0x71},
{0x6e, 0x88},
{0x58, 0x5E},
{0x6d, 0x40}, // STP cable for FPD
{0xd5, 0xf0}
// Serializer and sensor I2C id and Alias programming
Ser : {Reg Address, Reg Value}
{0x02, 0x33},
{0x0E, 0x1E},
{0x0D, 0xE1}
Does the deser require some other specific configuration to output the CSI-clock in the expected manner.
Please guide us for getting the correct signal in CSI-clock
Thanks in advance
Best Regards,
Ranjith Bhide
