DS250DF230: DS250DF230

user6207997

Part Number: DS250DF230

Hi:

I'm using DS250DF230 in the design, and I'm doing the PRBS test. The link under test is like this:

322.265625MHz -> CABLE -> Retimer (10.3125Gbps) -> oscilloscope

I want to use the retimer to generate PRBS. But after I configured the registers, there're no signal outputs. My configuration sequence is shown below:

Referenced from Programmer's guide(SNLU182D)

// Configuration
0xFC, 0x01 , 0xFF
0xFF, 0x03 , 0x03
0x0A, 0x0C , 0x0C

0x60, 0x90 , 0xFF
0x61, 0xB3 , 0xFF
0x62, 0x90 , 0xFF
0x63, 0xB3 , 0xFF
0x64, 0xFF , 0xFF
0x09, 0x04 , 0x04
0x18, 0x10 , 0x70

0x1E, 0x00 , 0x10
0x0A, 0x00 , 0x0C

//PRBS gen
0x2E, 0x04 , 0x04
0x30, 0x01 , 0x03
0x1E, 0x10 , 0x10
0x79, 0x00 , 0x20
0x79, 0x20 , 0x20
0x30, 0x00 , 0x08
0x30, 0x08 , 0x08
0xA5, 0x80 , 0xE0

Any advice will be appreciated, thanks!

over 3 years ago

0 Rodrigo Natal over 3 years ago

TI__Mastermind 19135 points

Hi,

Can you confirm whether you are using CAL_CLK_IN = 25MHz on your board?

Cordially,

Rodrigo Natal

HSSC Applications Engineer

0 user6207997 over 3 years ago in reply to Rodrigo Natal

Prodigy 60 points

Hi, Rodrigo

I have confirmed that I'm using CAL_CLK_IN = 25MHz(50ppm) on my board.

Regards,

0 Rodrigo Natal over 3 years ago in reply to user6207997

TI__Mastermind 19135 points

Hi,

What values are you observing for the channel registers below on the retimer channel in question that you are working to configure as PRBS generator?

0x02
0x27
0x28
0x78
0x8F

Cordially,

Rodrigo Natal

HSSC Applications Engineer

0 user6207997 over 3 years ago in reply to Rodrigo Natal

Prodigy 60 points

Hi,

I observed the below channel register values.

0x02 -> 0x00

0x27 -> 0x00

0x28 -> 0x00

0x78 -> 0x20

0x8F -> 0xEA

Regards,

0 Rodrigo Natal over 3 years ago in reply to user6207997

TI__Mastermind 19135 points

Hi,

The retimer CDR does not appear to be locking to your 322.265625MHz reference signal. Some additional suggestions

Can you try the next sub-rate frequency up, 644.53125MHz?
What signal amplitude are you using, can you try increasing it?
Try manually forcing CTLE = 0x00 on this PRBS generator channel. See below.

Table. Set CTLE Boost Value

STEP

SHARED/ CHANNEL REGISTER SET

OPERATION

REGISTER ADDRESS [HEX]

REGISTER VALUE [HEX]

WRITE MASK [HEX]

COMMENT

Channel

Write

Enable CTLE boost override

Channel

Write

Set CTLE boost to 0x00.

Interface

Interface forum

DS250DF230: DS250DF230