DS90UB960-Q1: Cant obtain lock

I should also mention that I can read register 0x5B and get 0x30. 

I did some more tests and captured the lock status using a GPIO.

Hello Jon,

can you give more details about your system? For example

Used MODE on SER and on DES?

Clock source and value on both devices?

Can you provide register dump from both devices?

Hi Hamzeh

The mode is CSI-2 on both devices. The DES has a 25MHz oscillator and the SER uses the channel clock. Below is the register dump from the DES. I cant do it for the SER as it wont let me read the registers consistently. I guess because the link isnt stable.

Thanks

Jon

addr = 4C data = 12
addr = 00, data = 60
addr = 01, data = 00
addr = 02, data = 1E
addr = 03, data = 40
addr = 04, data = D0
addr = 05, data = 01
addr = 06, data = 00
addr = 07, data = FE
addr = 08, data = 1C
addr = 09, data = 10
addr = 0A, data = 7A
addr = 0B, data = 7A
addr = 0C, data = 0F
addr = 0D, data = B9
addr = 0E, data = 07
addr = 0F, data = FF
addr = 10, data = 00
addr = 11, data = 00
addr = 12, data = 00
addr = 13, data = 00
addr = 14, data = 00
addr = 15, data = 00
addr = 16, data = 00
addr = 17, data = 00
addr = 18, data = 00
addr = 19, data = 00
addr = 1A, data = 00
addr = 1B, data = 00
addr = 1C, data = 00
addr = 1D, data = 00
addr = 1E, data = 04
addr = 1F, data = 02
addr = 20, data = F0
addr = 21, data = 03
addr = 22, data = 00
addr = 23, data = 00
addr = 24, data = 00
addr = 25, data = 00
addr = 26, data = 00
addr = 27, data = 00
addr = 28, data = 00
addr = 29, data = 00
addr = 2A, data = 00
addr = 2B, data = 00
addr = 2C, data = 00
addr = 2D, data = 00
addr = 2E, data = 00
addr = 2F, data = 00
addr = 30, data = 00
addr = 31, data = 00
addr = 32, data = 00
addr = 33, data = 00
addr = 34, data = 00
addr = 35, data = 00
addr = 36, data = 00
addr = 37, data = 00
addr = 38, data = 00
addr = 39, data = 00
addr = 3A, data = 00
addr = 3B, data = 00
addr = 3C, data = 00
addr = 3D, data = 00
addr = 3E, data = 00
addr = 3F, data = 00
addr = 40, data = 00
addr = 41, data = A9
addr = 42, data = 71
addr = 43, data = 01
addr = 44, data = 00
addr = 45, data = 00
addr = 46, data = 20
addr = 47, data = 00
addr = 48, data = 00
addr = 49, data = 00
addr = 4A, data = 00
addr = 4B, data = 12
addr = 4C, data = 12
addr = 4D, data = 50
addr = 4E, data = EB
addr = 4F, data = 00
addr = 50, data = 00
addr = 51, data = 00
addr = 52, data = 00
addr = 53, data = 02
addr = 54, data = 00
addr = 55, data = 00
addr = 56, data = 00
addr = 57, data = 00
addr = 58, data = 1E
addr = 59, data = 00
addr = 5A, data = 00
addr = 5B, data = 30
addr = 5C, data = 00
addr = 5D, data = 00
addr = 5E, data = 00
addr = 5F, data = 00
addr = 60, data = 00
addr = 61, data = 00
addr = 62, data = 00
addr = 63, data = 00
addr = 64, data = 00
addr = 65, data = 00
addr = 66, data = 00
addr = 67, data = 00
addr = 68, data = 00
addr = 69, data = 00
addr = 6A, data = 00
addr = 6B, data = 00
addr = 6C, data = 00
addr = 6D, data = 7C
addr = 6E, data = 88
addr = 6F, data = 88
addr = 70, data = 6B
addr = 71, data = 6C
addr = 72, data = E4
addr = 73, data = 00
addr = 74, data = 01
addr = 75, data = FF
addr = 76, data = FF
addr = 77, data = C5
addr = 78, data = 00
addr = 79, data = 01
addr = 7A, data = 0F
addr = 7B, data = FF
addr = 7C, data = 20
addr = 7D, data = 00
addr = 7E, data = 00
addr = 7F, data = 00
addr = 80, data = 00
addr = 81, data = 00
addr = 82, data = 00
addr = 83, data = 00
addr = 84, data = 00
addr = 85, data = 00
addr = 86, data = 00
addr = 87, data = 00
addr = 88, data = 00
addr = 89, data = 00
addr = 8A, data = 00
addr = 8B, data = 00
addr = 8C, data = 00
addr = 8D, data = 00
addr = 8E, data = 00
addr = 8F, data = 00
addr = 90, data = 00
addr = 91, data = 00
addr = 92, data = 00
addr = 93, data = 00
addr = 94, data = 00
addr = 95, data = 00
addr = 96, data = 00
addr = 97, data = 00
addr = 98, data = 00
addr = 99, data = 00
addr = 9A, data = 00
addr = 9B, data = 00
addr = 9C, data = 00
addr = 9D, data = 00
addr = 9E, data = 00
addr = 9F, data = 00
addr = A0, data = 00
addr = A1, data = 00
addr = A2, data = 00
addr = A3, data = 00
addr = A4, data = 00
addr = A5, data = 1C
addr = A6, data = 00
addr = A7, data = 00
addr = A8, data = 00
addr = A9, data = 00
addr = AA, data = 00
addr = AB, data = 00
addr = AC, data = 00
addr = AD, data = 00
addr = AE, data = 00
addr = AF, data = 00
addr = B0, data = 1C
addr = B1, data = 3A
addr = B2, data = 15
addr = B3, data = 08
addr = B4, data = 25
addr = B5, data = 00
addr = B6, data = 18
addr = B7, data = 00
addr = B8, data = 8C
addr = B9, data = 33
addr = BA, data = 83
addr = BB, data = 74
addr = BC, data = 80
addr = BD, data = 00
addr = BE, data = 00
addr = BF, data = 00
addr = C0, data = 00
addr = C1, data = 00
addr = C2, data = 00
addr = C3, data = 00
addr = C4, data = 00
addr = C5, data = 00
addr = C6, data = 00
addr = C7, data = 00
addr = C8, data = 00
addr = C9, data = 00
addr = CA, data = 00
addr = CB, data = 00
addr = CC, data = 00
addr = CD, data = 00
addr = CE, data = 00
addr = CF, data = 00
addr = D0, data = 00
addr = D1, data = 43
addr = D2, data = 94
addr = D3, data = 3F
addr = D4, data = 60
addr = D5, data = F2
addr = D6, data = 00
addr = D7, data = 03
addr = D8, data = 00
addr = D9, data = 00
addr = DA, data = 04
addr = DB, data = 6B
addr = DC, data = 00
addr = DD, data = 00
addr = DE, data = 00
addr = DF, data = 00
addr = E0, data = 00
addr = E1, data = 00
addr = E2, data = 00
addr = E3, data = 00
addr = E4, data = 00
addr = E5, data = 00
addr = E6, data = 00
addr = E7, data = 00
addr = E8, data = 00
addr = E9, data = 00
addr = EA, data = 00
addr = EB, data = 00
addr = EC, data = 00
addr = ED, data = 00
addr = EE, data = 00
addr = EF, data = 00
addr = F0, data = 5F
addr = F1, data = 55
addr = F2, data = 42
addr = F3, data = 39
addr = F4, data = 36
addr = F5, data = 30
addr = F6, data = 00
addr = F7, data = 00
addr = F8, data = 00
addr = F9, data = 00
addr = FA, data = 00
addr = FB, data = 00
addr = FC, data = 00
addr = FD, data = 00
addr = FE, data = 00

Hello Jon,

Please give us a day or two to review your registers and provide feedback. Thanks!

-Casey 

Hi Casey

OK thanks

Jon

Hello Jon,

- Which RX Ports are you using? reg0x04 - LOCK SEL is set for all enabled Ports.
- Can you try in reg 0x58=0x5D instead of 0x1E?

Hi Hamzeh

At the moment I am just using RIN2 port. I tried register 0x58 as 0x5D but it didnt make any difference

Regards

Jon

Hello Jon,

Thanks for the feedback.

In your position I would try a different cable type/length, say 2m and 5m or 8m.

Also you should check the PoC filter, if you have one, and measure the noise on the filter.

Other reasons for toggling LOCK would be for example:
- Quality of input PCLK? (jitter, etc.)
- Impedance matching of your Input/Output connectors and boards.
- Power supply noise?
- LVCMOS inputs – overshoot, undershoot?
- Quality of serial data eye diagram?

Hi

How critical is the front end routing? The front end I have isn't 50R. I also have a through hole connector that is routed on the top layer so there will be a stub. I know these things are not ideal but are they enough to stop the link working? I also did a small test where I attached one of our serializer boards to the input capacitors and but still no consistent lock. I was a bit surprised by this as the length of the connection was only about 5mm. The input clock I have is the same one as on the eval board and also the MIPI outputs work fin in test gen mode. My power supplies have less then 10mV of noise on them. I cant check the eye as I dont have a scope fast enough to do that. 

Regards

Jon

Hello Jon,

minimum supported cable between SER and DES should be more than 33 cm, so using a 5mm wire is not a valid use case.

Have you tested with longer cable, as I said in my previous post? Longer cable will help to reduce reflections, if the issue is refelections.

Hi Hamzeh

OK I didnt realize the devices needed a min cable length. I will try with longer cables

Thanks

Jon