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4956 Discussions

Using external clock to drive FPGA DE10-Nano

Syouf
Novice
620 Views

Hello,

I am working on a project in which I need to use the clock of DE2-115 to drive a DE10-Nano FPGA. I connected the clock signal of the DE2 to one of its GPIO pins, and connected that pin to a GPIO pin on the DE10 and used it as my input clock. I believe that I've made a mistake, but I don't know what is it, or how to solve it. When I try to see the signals using the SignalTap analyzer, a 'waiting for clock' message is displayed, as if the clock is not detected.

Any sort of help is much appreciated.

Regards,

0 Kudos
17 Replies
IDeyn
New Contributor III
605 Views

Hi Syouf!

Maybe you doesn't exploit dedicated clock pins? Do you use PLL on DE10-Nano board?

It's not a good practice to use external clock through GPIO because of jitter requirements.

 

You can attach your project or made a more detailed description of your layout. 

 

--

Hope it helps,

Ivan

Syouf
Novice
589 Views

Hi Ivan,

I want to use the DE10-nano as an ADC only, and send the digital output to another FPGA (the DE2-115) using the GPIO pins. When I used the internal clock of the DE10, everything was working properly. After that, what I did is that I changed the pin assignment of the clock from the internal clock to an external GPIO pin at which I connected the clock that is coming from the DE2 board. I did no other modifications.

I hope that this gives you a good image of what I've done. I used no PLLs, and yes I didn't exploit the dedicated clock pins and I don't know how to do that, I am new to FPGAs. All that I've done is that I outputted the clock of the DE2 to one of its GPIO pins and connected it to a GPIO pin on the DE10 and assigned that pin to the clock of the DE10 board with no other modifications.

Please let me know if you need more details. Your help is much appreciated

IDeyn
New Contributor III
583 Views

Hi Syouf,

 

Well, in that case I agree with JohnT_Intel, please ensure that you're using same IO standard for clock pins

on both boards. 

You can still attach your schematic or project archive for more prompt assist. 

 

--

Hope it helps,

Ivan

Syouf
Novice
567 Views

Hello Guys,

I am using a clock frequency of 50 MHz. I believe that I am using the same IO standards. Here attached the project files for both the systems. 

The project in the "DE2" folder takes 8 digital inputs from its GPIO pins ( coming from the DE10-Nano board's ADC) and forwards them properly to the DAC in the DE2-115 VGA port to output the analog signal. Also, the input clock of this system is outputted at one of the GPIO pins to be connected to a GPIO pin on the DE10-Nano board to be used as the clock there.

The project in the "DE10" folder uses the internal ADC in the DE10-Nano board to convert an input analog signal to digital signal and sends the 8 MSBs of the conversion results to its GPIO pins that are connected to the DE2-115 board. The clock of this system is provided through a GPIO pin from the DE2-115 board. when I was using an internal clock from the DE10-Nano board (with no connection to the other board), this system was working properly. Now, with the clock being provided from the DE2-115 board through a GPIO pin, the board seems to fail to detect the clock, as per the signal tap logic analyzer.

I hope that everything will be clear now. Many thanks for your support, it is greatly appreciated.

IDeyn
New Contributor III
561 Views

Hi Syouf,

Yes, you need to specify I/O standards for your pins using Pin Planner or Assignments Editor, or directly in qsf file.



--
Hope it helps,
Ivan

Syouf
Novice
551 Views

Hello guys,

Thanks for your suggestions and recommendations. I specified the I/O standards for all the pins in both projects as 3.3V, the standard provided in the datasheets of the boards. The same issue persists, and the clock seems to be undetectable yet.

Is there any other suggestion? your support is highly valuable.

JohnT_Intel
Employee
585 Views

Hi,


May I know what is the clock frequency and IO standard use? Are you setting the same IO standard on both the DE2 and DE10 design?


JohnT_Intel
Employee
564 Views

Hi,


Thanks for sharing the project file. From the project, I observed that you do not set any IO standard on the pin. Could you try to set the specific IO standard used for each pin?


JohnT_Intel
Employee
549 Views

Hi,


May I know if you are able to use Oscilloscope to monitor the clock signal?


Syouf
Novice
540 Views

Hello,

Yes, I monitored the signal on a scope, and detected the 50MHz clock.

JohnT_Intel
Employee
533 Views

Hi,


Could you provide picture on how you connect the Clock and may I know where do you monitor the clock signal?


Syouf
Novice
521 Views

Hello,

Regarding the connection, I simply connected the AC15 pin from the DE2-115 to the AC24 pin on the DE10-Nano via a jumper, and used another jumper to connect the grounds. Anyway, although not needed, I attached a picture of the connection.

Regarding the monitoring, I tried to monitor the signal using the signal tap analyzer, but a "waiting for clock" message is displayed ( see the picture attached). When monitoring the signal coming out of the DE2, a 50 MHz signal is there (also attached). But, when trying to monitor the signal seen by the DE10, by assigning the value of the AC24 pin to another GPIO pin on the DE10 and monitoring the output on that pin, I only see noise. 

The scope that I use to monitor the signal is Agilent DS06102A

Regards,

 

IDeyn
New Contributor III
511 Views

Hi Syouf,

Ok, I see. Please attach project files updated with  I/O standards and with attached signal tap file for us to inspect your situation.

--
Hope it helps,
Ivan

IDeyn
New Contributor III
499 Views

Hi Syouf,

Please check the Voltage Level Setting of JP6 - Table 4-11

https://www.intel.com/content/dam/altera-www/global/en_US/portal/dsn/42/doc-us-dsnbk-42-1404062209-d...

 

--
Hope it helps,
Ivan

IDeyn
New Contributor III
494 Views

Hi Syouf,

It looks like you generate 2.5V clock and transmits it from DE2-115, so I suppose you need to change JP6 setting.

 

--
Hope it helps,
Ivan

JohnT_Intel
Employee
504 Views

Hi,


May I know if you monitor the signal on the clock provider board or the receiver board?


JohnT_Intel
Employee
492 Views

Hi,


Could you check if your board is using 2.5V VCCIO based on JP6 setting? In order to set it to 2.5V, you should short pin 5 and 6.


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