DS90UB954-Q1: using gpio pin output control to show status of csi2 tx port

We have 2 off 1920 x 1080 yuv422 bit streams that we are trying to line concatenate.

Would like to monitor the equivalent of the reg 0x25 and 0x22 bits that show that both ports are in sync , on a scope .

 so does the setting

RX Ports synchronized, RX Port 0 synchronized with RX Port 1 : bit pattern 101 100 x 1 in reg 0x12 achieve this , and is it active high output if true ?

Hi , so setup the 3 gpio to monitor frame valid signal from RX port 0 , the frame sync signal form dvice status register and csi 2 port rx port 0 synched with rx port 1

board.WriteI2C (UB954,0x0f,0x78) # 3 gpio as outputs

board.WriteI2C (UB954,0x10,0xc1) # gpio0 rx0 frame sync

board.WriteI2C (UB954,0x11,0x91) # device status register frame sync

board.WriteI2C (UB954,0x12,0x95) # csi 2 rx port 0 sync with rx port 1

what I observe on scope triggered on frame sync from 953 serialiser is

yellow trace frame sync  

cyan trace is rx port 0 frame valid signal

purple and green traces are from the sensor strobe frame sync signals

I am confused about the RX port frame valid signal as I assumed it would track with the start of the frame sync signal pulse .

Could someone explain what the pulse represents in this regards

I am trying to get the two ports to achieve line concatenation and thought that everything aligned to the frame sync pulse start would be sufficient for this .

any further suggestions appreciated

yes , the sensors are synchronised to the 953 frame sync signal and also both frame valid signals are the same on the scope traces when i set gpio 0 amd gpio 1 to reflect frame valid 

Took more scope screen grabs with GPIO set as follows

board.WriteI2C (UB954,0x10,0xe5) # gpio0 rx0 line sync : yellow trace

board.WriteI2C (UB954,0x11,0xe5) # gpio1 rx1 line sync : cyan trace

board.WriteI2C (UB954,0x12,0x91) # gpio2 synchronous csi 2 transmitter   : green trace

the purple trace in the first picture is the frame sync pulse

ALL traces synced to sync pulse signal generated from DS90UB954 and output form the 2 DS90UB953 serialiser to the image processor chips

You can clearly see that LV outputs are in sync and that the green trace [RX Ports synchronized, RX Port 0 synchronized with RX Port 1] is synced with the sync pulse.

Why is this ?

So the next picture shows the same signals except that purple is now the line valid output debug pin signal form a mipi to usb3 encoder device . Here the system is set for line concatenate with only port 0 or port 1 active in RX port forwarding control register.

here we get the expected 1920 x 1080 yuv 422 8 bit output displayed on pc

Now when we set both ports are active in RX port forwarding control register , we get the LV signals form the MIPI to USB3 chip terminate as the frame sync and CSI2 RX ports aligned signals go low.

so does the CSI2 RX ports aligned output track with the frame sync pulse ?

changed the frame sync to 50:50 and the csi2 rx ports locked does track with the frame sync signal.

################################################################################
# setup 50: 50 : fsync
################################################################################
board.WriteI2C (UB954,0x1a,0x00)
board.WriteI2C (UB954,0x1b,0xd9)
board.WriteI2C (UB954,0x1c,0x1c)
board.WriteI2C (UB954,0x18,0x03)

so in  the frame concat mode  , the cx3 seems to truncate at the same point above relative to frame sync start and halt at about  300uS after the start.,

I am not certain that the sensor are aligned enough , the purple trace shows only a couple of concatenated lines before output stops , is this the full output of the 954 line buffer ?

the USB3  debug shows only a frame size of 46088 bytes per frame during line concat mode

Hi Martin,

Can you check register 0x22 to see if the device tells you whether or not the sensors are synchronized?

Best,

Jiashow

using this code

for x in range(0,2000):
    print " sync register ",hex(board.ReadI2C(UB954,0x22,0x01))

when in line concat mode but just on port active we get 0x01 , when both ports set active via port forwarding control we get 0x00

so not in sync as far as the DS90UB954 is concerned

Hi , 

We had to dig deeper into the sensor ISP mipi settings and by changing THS exit parameter we are able to get 720p concatenation .

The goal is still to get 1080p and what we observe at present is that the first 14..16 lines are ok then the image starts to streak with banding . 

We believe that this is in the mipi to usb  converter device and not any 954 setting per se .

Will attach screen grabs later , showing the artefacts in case anyone has observed something similar.

regards 

Attached is the displayed output .