DS125DF410: CDR Setting

I try your data. but a video signal was not output.

By the way,when a video signal was not output that I showed,  a value of Retimer's Addr 0x02 was 0x00.

Do you know what it is from this value?

Regard.

Hi,team.

An answer becomes slow,and I am sorry.
The detailes thing cannot say, but the application uses the high speed signal using the IP of FPGA.

Hi,team.

I inform it of the setting value which i set some other day
because setting value of CTLE which I showed had an omission of mention.

■Data rate setting
REG DATA
0x2F 0xB6
0x60 0x66
0x61 0xBB
0x62 0x66
0x63 0xBB
0x64 0xFF

■CTLE setting(15dB fixing)
REG Data
0x31 0x00
0x03 0x52
0x2D 0x88
0x3A 0x52
0x40 0x52

The setting of data rate is calculated by a calculation methed listed in datasheet.
Retimer works by this setting normally under the normal temparature environment(abut 25～28℃).
But, specific channel of Retimer dose not lock under low temperature enviroment(-5℃).
Therefore FPGA of the latter half can not recieve a signal.

When this problem was occured, FPGA was not able to recieve a signal was able to recieve a signal
when I switched to setting to bypass CDR.

■CDR Bypass mode
REG Data
0x09 0x20
0x1E 0x09

When CDR was validated, REG 0x02 Data 0x00.
When CDR was bypassed, REG 0x02 Data 0xDC.

From these results, I think that CDR dose not function.
What should I do to functionalize CDR effectively?

When there is not the method that CDR functionalizes, I want to adopt a CDR bypass mode.

Is there not the problem by this how to use?

Best regards.

Hi, nasser.

> 1). When measuring -5degC, at what point are you making this measurement?

A trial product is put in a constant temparature tank.

I set the temparature setting of the constant temparature tank to -5 degC.

>2). There is a way you can enable the device to go into raw mode when device is not locked. Please below note register settings for this operation:
>Reg 0x09[5]=1'b1 //set bit 5 of reg 0x09
>Reg 0x1E[7:5]=1'b000 //set bits 7 through 5 of reg 0x1E to 0000

The setting mentioned above has already set it.

Dose the raw mode come by a movement guarantee as DS125DF410?

Had it not been for setting to be able to lock, I want to operate it with raw mode.

Best regard.

Hi, nasser.

> 1). I am trying to understand the temperature DS125DF410 device is exposed to. Your temperature tank could be at -5degC but
> how about DS125DF410 device. Is this also at -5degC or lower? DS125DF410 is rated at -85degC.

Because I put a board in a tank, probably I think that the temparature of DS125DF410 device reach approximately -5 degC.
-5 degC is temparature to evaluate of the products.

> 2). You said: Does the raw mode come by a movement guaranteed by DS125DF410".
> Here I am assuming you mean does DS125DF410 go into raw mode if there is no lock and the answer is yes. DS125DF410 -
> using register settings that I noted earlier - will go into raw mode if device is not locked

I examine it in various ways and use raw mode if there is not at method to lock.

By the way, data of reg 0x02 was 0xDC at raw mode.
Though CDR is not used, why dose data of reg 0x02 become 0xDC?

Best regard.

Hi,Nasser.

Is MUX which you say a part of the red frame of figure which I attached?

Regard.

 MUX_of_Block_Diagram.pptx

Hi.Nasser.

When I watched Block diagram which have pointed, 

only pattern generator and the signal which is output from CDR is input to the MUX.

The output from CTLE dose not seem to be connected directly?

Actually, is the output from CTLE connected to MUX directly,too?

Regard.

It is guessed by your comment so that there MUX to change the path which does not go by way of CDR and tha path going way of CDR in CDR/Retimer.

I think that it become like the document which I attached.

Dose my recognition match yuor recognition?

MUX_of_Block_Diagram2.pptx 

Hi, Nasser.

when the path which dose not go by way of CDR was used, data of Reg 0x02 was 0xDC(Values of Reg 0x02 bit 4:3 ware 1)

Though the path going by way of CDR is not used, why ware values of Reg0x02 bit4:3 1 (CDR Lock) ?

Regard.

Hi, Nasser.

Thank you for a replay.

I understand that reg 0x02[4:3]=2'b11 when  a signal dose not go by way of CDR.

Just I have a quesion.

If a signal goes by way of CDR at same setting as raw mode(setting other than raw mode setting),

reg 0x02 = 0x00 in my retimer. Of course 0x02[4:3] =2'b00.

I want to know why it become reg 0x02 = 0x00(0x02[4:3] =2'b00).

Please tell me if there are points to be confirmed.

Regard.

Hi,Nasser.

When switching from the path which dose not going by way of CDR to the path going by way of CDR, CDR is not locked.  

The same signal is input to CDR as when bypassing CDR, but why is CDR is not locked?

Regard.

Hi,Nasser.

 >If I understand you correctly, you put DS125DF410 in bypass mode and you observe device is locked. Then you change mux settings to enable retimer path then you notice CDR is not locked.

>If this understanding is correct, please note the following:

Your understanding is correct.

>1). First of all, please make sure you read lock indication to be certain device is locked.

When I switch from CDR mode to bypass mode, The data of reg 0x02 switches from 0x00 to 0xDC.

>2). When device is in bypass and CDR is locked, please change your CTLE settings to make sure you have good HEO/VEO eye opening margin.

>Suggestion is to optimize your CTLE settings so you would get HEO about 0.7UI and VEO in order of at least 250mV or higher.

>In my case and at 5.94Gbps, when I switch from bypass to retimed mode device stays lock. Please note getting good HEO/VEO number(VEO more than 300mV and HEO about 0.75UI).

The value of HEO and VEO at raw mode are as follows.

            ch0                     ch1                       ch2                       ch3    HEX(DEC)

HEO   0x20(0.514UI)     0x23(0.5521UI)    0x26(0.5938UI)    0x22(0.5313UI)

VEO   0x8A(431.3m      0x7C(390.6mV)   0x8F(446.9mV)     0x88(428.1mV)

>3). When you switch from bypass to retimed mode and CDR is not locked, please do the followings:

>Put device in adapt mode 1 or adapt mode 2 and then reset CDR. Does this enable device to lock?
 

Regerd.

Hi, Nesser.

I understand.Thank you for your help

Hi Nasser

I sent update information via e-mail to Shidara-san this morning.

Please discuss with Shidara-san.

Regard.