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About configuration in AS mode


I plan to use MT25QU256A as Arria10 configuration ROM.

It will be used in AS mode, but it would be helpful if you could teach me about some points in the description of the handbook.

1) The description of CLKUSR in Figure 133 says, "The CLKUSR pin can be used to supply an external clock source to drive DCLK during configuration." Use the CLKUSR pin to provide an external clock source to drive DCLK during configuration." The latter is described as required, but which is correct?

2) Although it overlaps with the above, is it correct to recognize that it is essential to supply an external clock to CLKUSR in AS mode?


I'm sorry to trouble you, but it would be helpful if you could teach me.

Also, please forgive me for the fact that it is a machine-translated sentence that is not in English.

that's all

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2 Replies

Hi Yamada1,


You can refer to the user guide under sub-topic DATA Clock (DCLK) on page 227 in the Intel® Arria® 10 Core Fabric and General Purpose I/Os Handbook. It does mention that the Arria 10 devices drive control signals on the falling edge of DCLK and latch the configuration data on the following falling edge of this clock pin. You can source DCLK using CLKUSR or the internal oscillator.


You can refer 7.3.2. CLKUSR on page 249 for additional explanation on CLKUSR. I hope this would clarify your concern








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Hi Yamada1,

I would like to kindly follow up with you to inquire if you have any additional concerns regarding this case. Please do not hesitate to inform us if there are any outstanding issues, as we are always available to provide further assistance.

However, if there are no further updates or feedback from you, please be advised that this thread will be marked as inactive and subsequently transitioned to community support. I kindly request that you keep me informed of any progress or changes in the situation. Thank you for your attention to this matter, and I look forward to hearing from you soon.

Best regards,


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