How to implement a tri-state buffer

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christoph_hesse
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How to implement a tri-state buffer

Hello,

My design involves 12 3-state buffers to be implemented. I am quite new to Greenpak and I didn't find 3-state buffers in the doc. I only find that 3-state buffers are integrated in the Pins. 

However, my design involves 5 3-state outputs going into an OR Gate (LUT), for instance. 

Is it possible to route the output of a 3-state buffer to an internal LUT or generally route it internally? Or do I have to go out of the chip through the Pin 3-state and back in through another Pin? I would run out of Pins then. 

If this information is somewhere in the docs, please point me to it! Thank you.

(I think the concept of a 3-state buffer is clear, like verilog

assign output = enable ? input : 1'bz;

)

Thanks so much!

Christoph  

 

Device: 
Device Number: 
SLG46533
pavloZ
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Hi Christoph,

Hi Christoph,

unfortunately, no there is no possibility to implement a tri-state buffer internally just using the PIN as the buffer. I'm wondering why do you need tri-state outputs if then they connected to an OR gate? Could you please provide this part of the schematic diagram for better understanding your requirements? Hope it can be replaced by muliplexer.

Thanks and regards,

Pavlo

christoph_hesse
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Hi Pavlo, thanks for your

Hi Pavlo, thanks for your quick reply. I have attached a schematic. It is a bit quirky as I just have powerpoint here. 

This Schematic shows 2 in/outs D1 and D2 on the right side. In fact, I will have 5 that are connected just as 1 and 2 are now. 

If I need more than one Greenpak to implement this and not only one, it would probably still be advantageous over other solutions, and therefore ok. But ideally I would like to implement it with one IC only.

Could you take a look if and how I could implement it using Greenpak? Thanks

Attachment: 
olehs
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Hi Christoph, 

Hi Christoph, 

Thank you for your schematics. Please see the attached file. I created the reference design for you using SLG46533. 

Hope it helps you start.

Best regards, 

Oleh