DS250DF230: CDR could not be lock at TX/RX

Cindy Chang

Part Number: DS250DF230
Other Parts Discussed in Thread: DS250DF410,

Hi team,

Customer used a 2-port 25G network interface card and found that CDR could not be lock at TX and RX, ie register 0x78 = 0x20.

However, when they used a 4-port 25G network interface card for DS250DF410, CDR could be lock.(register 0x78 = 0x30)

These 2 cards are with the same 25.78125G clock source and 2 IC are in default value (adapt mode 1).

Do you have any idea how we could resolve this issue on DS250DF230?

Thank you.

Best Regards,

Cindy

over 4 years ago

0 Drew Miller1 over 4 years ago

TI__Mastermind 38703 points

Hi Cindy,

I am looking into this and will get back to you with more details tomorrow.

Best Regards,

Drew Miller

0 Rodrigo Natal over 4 years ago

TI__Mastermind 19235 points

Hi,

What is the retimer CAL_CLK_IN frequency being used by the customer, is it 25MHz? If it is 25MHz, the customer should configure the DS250DF230 for 25.7815Gbps CDR rate via the channel register settings per the table below.

Table 25. Register Settings for Common Data Rates using 25-MHz Calibration Clock

DATA RATE	REG_0x60 VALUE [HEX]	REG_0x61 VALUE [HEX]	REG_0x62 VALUE [HEX]	REG_0x63 VALUE [HEX]	REG_0x18[6:4] VALUE [HEX]
25.78125 Gbps (1)	74	C0	74	C0	0
25.0 Gbps (1)	80	BE	80	BE	0
20.625 Gbps	90	B3	90	B3	0
12.5 Gbps (1)	80	BE	80	BE	1
10.3125 Gbps (1)	90	B3	90	B3	1

Regards,

Rodrigo Natal

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DS250DF230: CDR could not be lock at TX/RX