added DMA tutorial

_posts/2024-7-21-HDL_in_120s.md

@@ -8,7 +8,7 @@ math: false
 mermaid: false
 image:
   path: https://www.guiahardware.es/wp-content/uploads/2023/08/HDL.jpg
-  alt: Zynq SoC
+  alt: HDL in 120s
 ---
 # Building your own AXI LED IP
 

_posts/2024-7-28-DMA_FFT_ON_ZYNQ.md

@@ -0,0 +1,58 @@
+---
+title: "Direct Memory Access (DMA) : A hands on Zynq example"
+date: 2024-7-21 15:00:00 +0800
+categories: [Tutorials, Zynq]
+tags: [fpga, beginner, C]
+pin: false
+math: false
+mermaid: false
+image:
+  path: https://media.geeksforgeeks.org/wp-content/uploads/20240109112312/screen.png
+  alt: DMA Overview
+---
+
+# DMA Tutorial : A hands-on example using Fast Fourier Transform (FFT) IP
+
+Based on this [video](https://youtu.be/aySO9jCKj9g).
+{% include embed/youtube.html id='aySO9jCKj9g' %}
+
+> Level : Beginner +. If you come from the "begginer" section tag, please make sur you did the "implementing your own IP" tutorial (or that you have similar knowledge).
+{: .prompt-info }
+
+## [Find the example FFT DMA bare-metal firmware here](https://github.com/0BAB1/BRH_Tutorials/tree/main/4%20DMA%20tutorial)
+
+## Intro
+
+DMA is a way to access memory without using loads instructions from you CPU.
+
+The CPU asks the DMA to handle memory transactions for him, allowing the cpu to do more valuable tasks.
+
+> You can see DMA as a "memory co-processor"
+{: .prompt-tip }
+
+In this video, I walk you through a hands-on example to implement you first DMA on Zynq (or any FPGA if you know how to implement a softcore CPU) and how to interface it with an FFT IP as an exmaple device to leverage you IP designs without stalling to CPU to move data around.
+
+## Prerequisites
+
+- Know the basic of Vivado & vitis (see "implementing your own AXI LED IP" tutorial)
+- You **don't** need to understand FFT deeply to complete this tutorial, the FFT is just an exmaple.
+- Have vivado & vitis installed.
+
+## Video layout
+
+### 1 : What is DMA
+
+This first part is all about explaining what is DMA. It's pretty straight-forward.
+
+### 2 : Implementing a FFT IP (Hardware)
+
+This part is about putting all the hardware toghther. We don not implement a custom IP but a pre-made FFT IP from xinlinx to compute fourier transforms FAST !
+
+Given that we are not designing any IP this tutorial does not include any HDL.
+
+### 3 : Implementing a FFT IP (Software)
+
+In this part, We break down the firmware code logic and make our own firmaware so you can go on a make your own for your projects.
+
+> IMPORTANT NOTE if you plan on using UART like in the tutorial : do not use ```xil_printf()``` but rather ```printf()``` to handle the display of floats correctly.
+{: .prompt-warning }