DP83822I: Behavior of BMSR Link Status bit

Motoyasu Hattori

Genius 12590 points

Part Number: DP83822I

Hi,

After link is established from Power-up, does user read still "0" on 1st access of BMSR Link Status bit?

Also, after reading BSMR, during no link-up error, user read "1" on BMSR Link Status bit. Is it correct?

Please advise us.

Thanks and best regards,
M.HATTORI.

over 5 years ago

0 Vikram Sharma over 5 years ago

TI__Genius 16030 points

Hello Hattori-san,

Link status bit is a "latch-low" bit. So even if link recovers after going low , first read will read 0 and then onwards it will become 1.

Regards,

Vikram

0 Motoyasu Hattori over 5 years ago in reply to Vikram Sharma

TI__Genius 12590 points

Hi,

On my customer's board, he read "1" on 1st access of BMSR link status bit, after link is established from Power-up. Is this phenomena "correct operation"?

Your answer seems to read "0". If your answer is correct, he needs dummy read to clear link status bit. Please advise us.

Thanks and best regards,
M.HATTORI

0 Vikram Sharma over 5 years ago in reply to Motoyasu Hattori

TI__Genius 16030 points

Hello Hattori-san,

To be specific, here is how it is coded :

1. power up => no link-up => first read of link status : link-status bit = 0.

2. power up => link-up => first read of link status : link-status bit = 1

Regards,

Vikram

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DP83822I: Behavior of BMSR Link Status bit