DS90UH948-Q1: How to enable "Auto clock enable"

Ryuuichi machida

Guru 12715 points

Part Number: DS90UH948-Q1

Hi,

I confirmed function of 0x02[5] (Auto Clock Enable).

Here is procedure which I performed.

1. Connect DS90UH929 EVM and UH948. And power on both EVMs.

2. Set internal pattern generator of DS90UH929. (Confirmed 25Mhz clock at UH948 OLDI pin and "LOCK" is high.)

3. Set 0x02[5] to 0x1 (Enable Auto clock Enable)

4. Disable internal pattern generator (Confirmed "LOCK" is low.)

I believe that I can see frequency which is set to 0x24[2:1] on CLK pin of OLDI.
However, I could not observe any frequency at CLK pin of OLDI.

Is there any incorrect procedure ?

Best Regards,

0 Liam Keese over 7 years ago

These bits 0x24[2:1] are only applicable for BIST mode. Bits 5:4 control the auto CLK_EN and default to 50MHz.

0 Ryuuichi machida over 7 years ago in reply to Liam Keese

Guru 12715 points

Hi Liam-san,

Thank you for your reply.

> Bits 5:4 control the auto CLK_EN and default to 50MHz.

Sorry, I forgot to describe about this.

I used default setting for Bits 5:4, however, I could not observe expected result (50MHz output from OLDI.).

Could you check on your EVM as well ?

Best Regards,

0 Liam Keese over 7 years ago in reply to Ryuuichi machida

please try disconnecting cable. It may be the 948 is still detecting and input clock

0 Ryuuichi machida over 7 years ago in reply to Liam Keese

Guru 12715 points

Liam-san,

>please try disconnecting cable.

I tried disconnecting cable b/w 929 and 948 EVM. But output clock was NOT observed...

Do you have any idea why I can get expected result ?

BR,

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