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2,950 Views
Registered: ‎10-23-2014

common clock for two processors

Hello,

I have a quad core imx6 processor and a zynq 7020 processor. Can I use a common external clock oscillator for these two? Is it sensible to do so? I want to do this to achieve synchronization.

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Moderator
Moderator
2,943 Views
Registered: ‎01-16-2013

@sunayana.chskradhar,

 

Yes,  think it would be better to use single clock to achieve synchronization.

Check the discussion on below forum thread:

https://forums.xilinx.com/t5/Timing-Analysis/synchronize-two-processors/td-p/244558

 

--Syed

 

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Guide
Guide
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Registered: ‎01-23-2009

I don't know what you mean by "achieve synchronization".

 

All CPUs do very complex things with clocks. There are PLLs and dividers, many of which are programmable. So even if they use the same oscillator, the relationship between the clocking of the cores is going to be complex. Furthermore, the phase of the clocks (even if they are the same frequency) will be unknown and unknowable.

 

So, what exactly do you mean by "acheive synchronization". Synchronization only matters when these two processors are interacting - how are they interacting? Do they share a common memory system? Do they have a common bus? Do they share some I/O?

 

If you answer these questions, or explain what it is you want, then maybe we can give you a more meaningful answer.

 

Avrum

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2,863 Views
Registered: ‎10-23-2014

I have a Intertial motion sensor, few GSMs and a wifi module connected to the FPGA. There is the same IMU connected to the imx6 and a ddr3dram, a flash memory too. I wanted both these processors to run at a common external clock but now i understand that this might not be feasible as both the processors in my set up have PLLs set by different divisio values (ex:*5 for fpga and *3 for imx). Its better that these proceessors work on the existing interna clock frequencies which is 33.33 MHz for zynq 7020 fpga and 32 kHz for imx6.

 

I also read the post mentioned in the link but there they have a common frequency for both the processors. Hence having a single common clock source would make sense there. Since my two processors work on different frequenies, they will have different clock dividers, so I guess its better not to use a commoon external clock in my case.

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