DS80PCI810: eye diagram results are different between SMBus slave mode and SMBus master mode (EEPROM)

CK Ho

Part Number: DS80PCI810

Dear sir,

Our customer is using DS80PCI810, but they found eye diagram results are different between SMBus slave mode and SMBus master mode (EEPROM).

First, for SMBus slave mode, they set EQ register value = 2D, VOD register value = AF, VOD_DB register value = 00.

The eye diagram result as below:

But using the same setting for SMBus master mode (EEPROM), the eye diagram result as below:

Why they are quite different !?

Attachments are the config file and hex file for EEPROM.

8272.c0.cfg

Is there something wrong for EEPROM programming??

Do you have any idea??

Thanks for your help in advance.

over 6 years ago

0 Lee Sledjeski over 6 years ago

TI__Mastermind 43795 points

The SMBus waveform has a lower amplitude in the pictures. Could you confirm the VOD_DB register reads are 0x00 and the Slave Register Control in register 0x06 = 18'h

Regards,

Lee

0 CK Ho over 6 years ago in reply to Lee Sledjeski

Expert 1780 points

Yes, the register 0x06 = 18'h.
Actually, the waveform of SMBus slave mode has "higher" amplitude than using SMBus master mode (EEPROM)

0 Lee Sledjeski over 6 years ago in reply to CK Ho

TI__Mastermind 43795 points

Sorry I read the information incorrectly. The SMBus waveform looks correct. After the EEPROM is finished the redriver will become an SMBus slave again. Could you verify the VOD_DB and VOD register information contains the expected values?

Thanks and Regards,

Lee

0 CK Ho over 6 years ago in reply to Lee Sledjeski

Expert 1780 points

Dear Lee,

Sorry, how could I verify?? Attachment below is the hex file for EEPROM. And this hex file is generated form the SigCon tool. I think it's correct.

By the way, I have another question. How should I arrange pin26 (SD_TH/READ_EN#) when using EEPROM in SMBus master mode?? Should I tie this pin to ground??

0 Lee Sledjeski over 6 years ago in reply to CK Ho

TI__Mastermind 43795 points

Yes tie the READ_EN# pin to GND and verify that the ALL_DONE# pin has gone "low" indicating a successful EEPROM load.

After ALL_DONE# has gone "low" it is possible to read the register contents just like SMBus slave mode.

Regards,
Lee

0 Lee Sledjeski over 6 years ago in reply to Lee Sledjeski

TI__Mastermind 43795 points

I am closing this thread with the assumption that pulling READ_EN# = Low solved the issue and allowed for a successful EEPROM load.
Regards,
Lee

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DS80PCI810: eye diagram results are different between SMBus slave mode and SMBus master mode (EEPROM)