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Visitor
Visitor
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Registered: ‎08-02-2019

HLS use UltraRam for fifo in dataflow region

Hello,

I have an HLS module that requires large FIFOs inside an dataflow region. I used hls::stream. For these i want HLS to use UltraRam, but i could not find a way how to tell HLS to biuld the FIFOs with ultra ram. 

The Resource pragma only allows FIFO, FIFO_LUTRAM, FIFO_BRAM and FIFO_SRL. I could think of splitting the module in two and put normal fifo ip's in between, but that is not really the preferred way. Is there a way to use ultraram in hls::stream fifos?

 

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Scholar
Scholar
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Registered: ‎04-26-2015

Re: HLS use UltraRam for fifo in dataflow region

@emc_three The fundamental problem is that, unlike BRAM, UltraRAM doesn't include FIFO hardware. Using it as a FIFO would require separate hardware implemented in LUTs, and it appears that neither HLS nor the Vivado FIFO generator knows how to do this.

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Visitor
Visitor
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Registered: ‎08-02-2019

Re: HLS use UltraRam for fifo in dataflow region

Hello, 

you are right, but the ip "Axis data fifo" does build that additional logic.

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