T2080 serdes pll is not lock occasionally！！

[zhylunwen]

Hello, I have a problem here. The SerDes PLL of T2080 is not locked occasionally, which is more obvious at low temperature. Please give me some advice，thanks！Attached is my RCW。

In addition, can T2080's SerDes protocol mode be configured as AA and 2D? I've tried this mode and it seems to work。

[zhylunwen]

Hi,ufedor ,thanks a lot. My sch and RCW arealready in the attachment above。Please help me find out what's wrong with my design。

[ufedor]

Please refer to the NOTE from the previous answer - the SerDes protocols combination 0xAA 0x29 is not supported.

[zhylunwen]

Is thers anything wrong with my sch？

[ufedor]

Please power down SerDes1 PLL2 and SerDes2 PLL2.

[zhylunwen]

Those two PLLs have been turned off, but the problem still exists。

[ufedor]

Please provide new RCW binary image.

You wrote:

> The SerDes PLL of T2080 is not locked

What exactly does it mean?

1) Please confirm that SerDes PLL reference clocks are stable before PORESET_B is deasserted.

2) Please provide a digital scope traces of the SerDes reference clocks at the processor's pins to check amplitude.

3) Please check that all supply voltages are within the processor's Data Sheet requirements.

[zhylunwen]

hi,ufedor,I've checked my voltage and clock and found no problem。But I found a strange phenomenon. When the USB tap is connected to the board（CodeWarrior software is not opened）, the SerDes PLL cannot be locked。

[ufedor]

The issue was not reported by other customers.

How the CodeWarrior TAP is powered?

Is common ground used for the board and the TAP?

[zhylunwen]

hello ufedor，the SerDes protocols combination 0xAA 0x29 can be found in codewarrior。And t2080 ce recommends that mode AB can be replaced by AA。

[ufedor]

Please provide additional information:

1) the processor connection schematics as searchable PDF for inspection

2) frequencies of all clocks applied to the processor

3) U-Boot booting log showing RCW (or binary RCW image)

> can T2080's SerDes protocol mode be configured as AA and 2D?

This configuration is not supported - refer to the QorIQ T2080 Reference Manual, 19.1.1.1.1 SerDes Protocols (SerDes 1 and SerDes 2):

"NOTE
The table below lists the SerDes protocol SRDS_PRTCL_S1 and SRDS_PRTCL_S2 combinations supported. When selecting protocols from the table below, there is a restriction to choose the supported protocol combinations by line (SerDes 1 and SerDes 2 together), for example SRDS_PRCTL_S1= A2 can ONLY be combined with SRDS_PRTCL_S2= 16"