SNLA386 May   2021 DS250DF810 , DS280DF810

 

  1.   Trademarks
  2. 1Introduction
  3. 2Reading Junction Temperature Procedure
  4. 3Extending Temperature Lock Range (TLR) Procedure
  5. 4Summary

3 Extending Temperature Lock Range (TLR) Procedure

The DS2X0DF810 retimer TLR can be extended to support CDR stay-in-lock between -40°C ambient temperature to 110°C junction temperature. This is accomplished by expanding on the internal junction temperature readback procedure shown in Section 2.

To extend TLR based on the internal junction temperature readback, the complete programming procedure in Table 3-1 should be included as part of the normal retimer programming procedure. For simplicity, this procedure is written assuming all channels in the retimer are being configured at the same time. Refer to the Common Device Configurations section of the DS2X0DF810 Programming Guide for example programming procedures.

Note: Insert this procedure just prior to the step where the CDR reset is asserted and de-asserted.
Table 3-1 Programming Procedure for Each Channel to Achieve Extended TLR
STEP REGISTER SET OPERATION

REGISTER ADDRESS

[HEX]

REGISTER VALUE

[HEX]

WRITE MASK

[HEX]

COMMENT
Normal Retimer configuration
Perform all steps to configure the Retimer as normal, except for the final step, which is to assert and de-assert the CDR reset. This step will be performed at the conclusion of this Extended TLR programming procedure.
Configure Retimer for temperature readback
1 Shared Write FF 10 FF Select Channel 0 – Channel 3 shared registers
2 Shared Write 04 40 40 Reset Channel 0 – Channel 3 shared registers
3 Shared Write FF 20 FF Select Channel 4 – Channel 7 shared registers
4 Shared Write 04 40 40 Reset Channel 4 – Channel 7 shared registers
5 Shared Write FF 10 FF Select Channel 0 – Channel 3 shared registers
6 Shared Write 0F 00 FF Enable temperature detection CH0-CH3
7 Shared Write FF 20 FF Select Channel 4 – Channel 7 shared registers
8 Shared Write 0F 00 FF Enable temperature detection CH4-CH7
9 Shared Write FF 03 FF Enable broadcast write to all channels, read from channel selected in Shared Reg_0xFC
10 Shared Write FC 04 0F Select single channel
11 Channel Write 0A 00 0C Release CDR from reset
12 Channel Write 14 80 80 Force-enable signal detect to ensure all channels are powered on prior to reading device temperature
13 Channel Write 19 01 C1 Enable channel temperature detection
14 Channel Write 18 01 03 Enable channel temperature detection
15 Shared Write FF 10 FF Select Channel 0 – Channel 3 shared registers
16 Shared Write 0C 00 38 Configure the input to the analog-to-digital converter (ADC)
17 Shared Write 0C 02 03 Enable ADC
18 Shared Write 0C 04 04 Reset ADC
19 Shared Write 0C 00 04 Set ADC to capture Analog Voltage
20 Wait 200 µs
21 Shared Write 0C 00 02 Disable ADC to freeze value
Temperature readback and Loop Filter Voltage calculation
22 Shared Read 0D -- -- DSAR[7:0] = Reg_0x0E[7:0]
23 Shared Read 0E -- -- DSAR[9:8] = Reg_0x0E[1:0]
  • Decimal_representation_of_temperature_code = (Reg_0x0E and 0x03) × 256 + Reg_0x0D
  • LPF_Setting = 0.44 × Decimal_representation_of_temperature_code – 55
    • If (LPF_Setting < 120), then LPF_Setting = 120

    • If (LPF_Setting > 210), then LPF_Setting = 210

  • Note: The numbers 256, 55, 120, and 210 in the previous equations are decimal numbers.
Configure Loop Filter Voltage
24 Shared Write FF 03 03 Enable broadcast write to all channels, read from channel selected in Shared Reg_0xFC
25 Channel Write 9D LPF_ Setting FF Configures the Loop Filter Voltage based on the results of the previous equation
26 Channel Write 17 25 FF Enable extended temperature lock range
De-activate device temperature sensing
27 Shared Write FF 10 FF Select Channel 0 – Channel 3 shared registers
28 Shared Write 04 40 40 Reset Channel 0 – Channel 3 shared registers
29 Shared Write FF 20 FF Select Channel 4 – Channel 7 shared registers
30 Shared Write 04 40 40 Reset Channel 4 – Channel 7 shared registers
31 Shared Write FF 03 FF Enable writing to all channels
32 Channel Write 19 00 C1 Disable channel temperature detection
33 Channel Write 18 00 03 Disable channel temperature detection
34 Channel Write 14 00 80 Undo force-enable of signal detect
Conclude normal Retimer configuration
35 Channel Write 0A 0C 0C Assert CDR reset
36 Channel Write 0A 00 0C De-assert CDR reset
37 Shared Write FF 01 01 Disable Broadcast write operation