DS90UB954-Q1: DS90UB954-Q1

Ian Wang

Part Number: DS90UB954-Q1

Dear Sir,

Pls advise to check about UB954 BCC_CONFIG(0x58) D[2:0] BC_FREQ_SELECT setting.

Referring to the description on spec, it should be configured to 50Mbps if our serializer is UB953.

But if we initial this register to 0x5e (BC_FREQ_SELECT -- 110 ; 50Mbps ) then we would get trouble to communicate via I2C.

Only setting to 0x5d (BC_FREQ_SELECT – 101 : 25Mbps), and the communicating by i2c is working properly.

Do you know why i2c can’t be working properly if set BC frequency to 50Mbps.

Thanks, Ian.

over 7 years ago

0 Steven(Shenzhen) Shi over 7 years ago

TI__Mastermind 30515 points

Ian,
In the sync. mode, the BC rate is set as 50Mbps, which is one main application for the combo between UB953/UB954, and we don't see any I2C communication issue in this BC rate.
for your issue, I would suggest you check the transmission channel performance, also whether the UB953 has BC CRC error?

regards,
Steven

0 Ian Wang over 7 years ago in reply to Steven(Shenzhen) Shi

TI__Mastermind 29770 points

Dear Steven,

I’d like to double confirm about how to check you point out the two possible reason in below.

Transmission channel performance – currently, our configure setting only one BC GPIO would be transmitted to serializer side.

How do I confirm it?

About you mention BC CRC error in below is meaning UB953 Reg(0x52 GENERAL_STATUS) D1 CRC_ERROR?

Thanks, Ian.

0 Steven(Shenzhen) Shi over 7 years ago in reply to Ian Wang

TI__Mastermind 30515 points

Ian,

please check the cable, connector, pcb trace and PoC network deign, which would impact the high speed signal integrity issue.

regarding the BC CRC error, please check UB953 d/s page17, the reg. 0x52/0x55/0x56 and 0x49 (CRC_ERR, CRC_ERR_CNT1/2, CRC_ERR_CLR) are used for back channel link quality monitor.

best regards,

Steven

0 Ian Wang over 7 years ago in reply to Steven(Shenzhen) Shi

TI__Mastermind 29770 points

Dear Steven,

Since change to 50Mhz BC channel related function can’t work properly, so it should be trouble to access 953 register which related to CRC error. We will confirm it tomorrow.

By the way, any side effect if we are selecting 25Mhz for BC freq.

Thanks, Ian.

0 Ian Wang over 7 years ago in reply to Ian Wang

TI__Mastermind 29770 points

Dear Steven,
Pls kindly check any side effect if we are selecting 25Mhz for BC freq.?
Thanks, Ian.

0 Steven(Shenzhen) Shi over 7 years ago in reply to Ian Wang

TI__Mastermind 30515 points

Ian,
as replied in another thread please note:
1. the 25Mbps bc rate is verified in the 2Gbps FC.
2. please check why it has bit error when running at 50Mbps, this is important! even if you run at 25Mbps, the system could still have potential issue.

regards,
Steven

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DS90UB954-Q1: DS90UB954-Q1