# Double array

**URL:** https://discuss.pynq.io/t/double-array/4456
**Category:** Support
**Created:** [July 13, 2022, 6:45pm UTC](https://discuss.pynq.io/t/double-array/4456 "2022-07-13T18:45:27Z")
**Posts on this page:** 1
**Showing post:** 6

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### Author: ![briansune](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.pynq.io/briansune/32/3087_2.png) [@briansune](https://discuss.pynq.io/u/briansune)
#### Post date: [July 13, 2022, 11:24pm UTC](https://discuss.pynq.io/t/double-array/4456/6 "2022-07-13T23:24:18Z")

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@alienflip  
In short there are tlast signal invoked during HLS.

 ![image](https://us1.discourse-cdn.com/flex019/uploads/pynq1/original/2X/3/38efda3921501266436157955b67e8c5db16877e.png)

However this is all related to the HLS design now.  
Debug using System-ILA via AXI-stream.

As previous post and this post already mentioned.  
DMA will only complete via tlast or data return # is met.

Try learning from this example:

> [@MNIST + AXI Stream on PYNQ 2.7 (Attention to Details)](https://discuss.pynq.io/t/mnist-axi-stream-on-pynq-2-7-attention-to-details/4267):
>
> Hello PYNQ community: I wish you all doing great =] Previous support posts are having trouble on AXI stream HLS about CNN design and DMA: So I am going to share the details on 2020.2 HLS tool and PYNQ 2.7 design. The Github Repository Link for this tutorial: HLS AXI Stream People keep asking about tlast is missing, which this is common that after version (not sure when) the structure C no longer interpret as we expected: Old struct AXI\_DMA\_IO{ ap\_int\<16\> data; ap\_int\<1\>last; }; New #in…

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