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Adam Taylor’s MicroZed Chronicles Part 80: LWIP Stack Configuration

by Xilinx Employee on ‎05-04-2015 09:32 AM (17,540 Views)

 

By Adam Taylor

 

We introduced the concept of the IP stack in the previous instalment of the MicroZed Chronicles. (See “Adam Taylor’s MicroZed Chronicles Chronicles Part 79: Zynq SoC Ethernet Part III.”) The next step is to use this stack in our design. The SDK development environment gives us the ability to include a lightweight IP stack (lwIP) when we create a BSP. lwIP is an open-source IP stack that’s used in a number of embedded systems. Originally it was developed by the Swedish Institute of Computer Sciences to reduce the resources required to create an IP stack.

 

Including lwIP in a Zynq-based design is very simple. You simply check the lwIP option on the BSP settings overview tab. If you are planning on using your Zynq system to host a web page, you will also need to check the xilmfs (Xilinx Memory File System) box to set up a file system within the Zynq system’s DDR memory.

 

 

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Once you have included this library, you can configure it by selecting lwIP under standalone as shown below:

 

 

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This option allows you to configure the lwIP as required, however your actual application will define parameters including IP addresses and subnets.

One way to use lwIP is to host a web page that provides system telemetry. You can use the same Web page to control the system using HTTP commands. These sorts of Web interfaces are very useful for Ethernet-connected embedded systems.

 

We’ll also need a file system to host a web page. The file system will be located within the Zynq SoC system’s DDR memory. The procedure for setting up this file system is very similar to the one for configuring the lwIP stack. Select the xilmfs option to define the memory location where the file system will reside:

 

 

 

Image3.jpg 

 

 

We can create a file using the mfsgen command in a Vivado tcl command line if required. We can also import webpages and pictures into the file system to be accessed by the lwIP stack using this command.

During software development, we will be using SDK and JTAG to download and run the lwIP application. As SDK downloads the ELF application, it must also download the file system memory contents to the correct location. This is achieved by adding a reference to the file system image created by mfsgen to the run or debug configuration. This image will then be downloaded to the correct memory location before the application executes so that it can find the required files (e.g. the websites to serve).

 

 

 Image4.jpg

 

 

 

With the file system and the lwIP installed correctly, we can now focus on application development. There are two main methods that we can use to interface our application to the lwIP stack:

 

  • Raw – This is the basic API to be used when no operating system is present. It is event-driven. Applications using the lwIP in this mode use call back functions for events like receiving data, etc.

 

  • Sockets – Used when the Zynq SoC is running an operating system. This method employs threads, which applications use to communicate with the lwIP stack.

 

 

A good example that pulls all of these concepts together and provides both Raw and Socket use cases can be found in XAPP1026 (LightWeight IP Application Examples), which implements a simple echo server and Web page server. Note that we are using the MicroZed board in this series and not the ZC7002 board so we need to use the port available on zedboard.org.

 

Going forward, I want to look at some very new and interesting developments in the Zynq world. I will be returning to this topic op IP use on the Zynq SoC in a little while.

 

Incidentally I am at the Embedded Systems Conference in Boston next week presenting on processor selection criteria for space-based applications. If you are attending this event, please drop by and say “hello.” It would be great to talk other Zynq users.

 

 

 

 

 Zynq 101 book cover.jpg

 

 

 

 

 

Now, you can have convenient, low-cost Kindle access to the first year of Adam Taylor’s MicroZed Chronicles for a mere $7.50. Click here.

 

 

 

Please see the previous entries in this MicroZed Chronicles series by Adam Taylor:

 

Adam Taylor’s MicroZed Chronicles Chronicles Part 79: Zynq SoC Ethernet Part III

 

Adam Taylor’s MicroZed Chronicles Chronicles Part 78: Zynq SoC Ethernet Part II

 

Adam Taylor’s MicroZed Chronicles Microzed Chronicles Part 77 – Introducing the Zynq SoC’s Ethernet

 

Adam Taylor’s MicroZed Chronicles Part 76: Constraints for Relatively Placed Macros

 

Adam Taylor’s MicroZed Chronicles, Part 75: Placement Constraints – Pblocks

 

Adam Taylor’s MicroZed Chronicles, Part 73: Physical Constraints

 

Adam Taylor’s MicroZed Chronicles, Part 73: Working with other Zynq-Based Boards

 

Adam Taylor’s MicroZed Chronicles, Part 72: Multi-cycle Constraints

 

Adam Taylor’s MicroZed Chronicles, Part 70: Constraints—Clock Relationships and Avoiding Metastability

 

Adam Taylor’s MicroZed Chronicles, Part 70: Constraints—Introduction to timing and defining a clock

 

Adam Taylor’s MicroZed Chronicles Part 69: Zynq SoC Constraints Overview

 

Adam Taylor’s MicroZed Chronicles Part 68: AXI DMA Part 3, the Software

 

Adam Taylor’s MicroZed Chronicles Part 67: AXI DMA II

 

Adam Taylor’s MicroZed Chronicles Part 66: AXI DMA

 

Adam Taylor’s MicroZed Chronicles Part 65: Profiling Zynq Applications II

 

Adam Taylor’s MicroZed Chronicles Part 64: Profiling Zynq Applications

 

Adam Taylor’s MicroZed Chronicles Part 63: Debugging Zynq Applications

 

Adam Taylor’s MicroZed Chronicles Part 62: Answers to a question on the Zynq XADC

 

Adam Taylor’s MicroZed Chronicles Part 61: PicoBlaze Part Six

 

Adam Taylor’s MicroZed Chronicles Part 60: The Zynq and the PicoBlaze Part 5—controlling a CCD

 

Adam Taylor’s MicroZed Chronicles Part 59: The Zynq and the PicoBlaze Part 4

 

Adam Taylor’s MicroZed Chronicles Part 58: The Zynq and the PicoBlaze Part 3

 

Adam Taylor’s MicroZed Chronicles Part 57: The Zynq and the PicoBlaze Part Two

 

Adam Taylor’s MicroZed Chronicles Part 56: The Zynq and the PicoBlaze

 

Adam Taylor’s MicroZed Chronicles Part 55: Linux on the Zynq SoC

 

Adam Taylor’s MicroZed Chronicles Part 54: Peta Linux SDK for the Zynq SoC

 

Adam Taylor’s MicroZed Chronicles Part 53: Linux and SMP

 

Adam Taylor’s MicroZed Chronicles Part 52: One year and 151,000 views later. Big, Big Bonus PDF!

 

Adam Taylor’s MicroZed Chronicles Part 51: Interrupts and AMP

 

Adam Taylor’s MicroZed Chronicles Part 50: AMP and the Zynq SoC’s OCM (On-Chip Memory)

 

Adam Taylor’s MicroZed Chronicles Part 49: Using the Zynq SoC’s On-Chip Memory for AMP Communications

 

Adam Taylor’s MicroZed Chronicles Part 48: Bare-Metal AMP (Asymmetric Multiprocessing)

 

Adam Taylor’s MicroZed Chronicles Part 47: AMP—Asymmetric Multiprocessing on the Zynq SoC

 

Adam Taylor’s MicroZed Chronicles Part 46: Using both of the Zynq SoC’s ARM Cortex-A9 Cores

 

Adam Taylor’s MicroZed Chronicles Part 44: MicroZed Operating Systems—FreeRTOS

 

Adam Taylor’s MicroZed Chronicles Part 43: XADC Alarms and Interrupts 

 

Adam Taylor’s MicroZed Chronicles MicroZed Part 42: MicroZed Operating Systems Part 4

 

Adam Taylor’s MicroZed Chronicles MicroZed Part 41: MicroZed Operating Systems Part 3

 

Adam Taylor’s MicroZed Chronicles MicroZed Part 40: MicroZed Operating Systems Part Two

 

Adam Taylor’s MicroZed Chronicles MicroZed Part 39: MicroZed Operating Systems Part One

 

Adam Taylor’s MicroZed Chronicles MicroZed Part 38 – Answering a question on Interrupts

 

Adam Taylor’s MicroZed Chronicles Part 37: Driving Adafruit RGB NeoPixel LED arrays with MicroZed Part 8

 

Adam Taylor’s MicroZed Chronicles Part 36: Driving Adafruit RGB NeoPixel LED arrays with MicroZed Part 7

 

Adam Taylor’s MicroZed Chronicles Part 35: Driving Adafruit RGB NeoPixel LED arrays with MicroZed Part 6

 

Adam Taylor’s MicroZed Chronicles Part 34: Driving Adafruit RGB NeoPixel LED arrays with MicroZed Part 5

 

Adam Taylor’s MicroZed Chronicles Part 33: Driving Adafruit RGB NeoPixel LED arrays with the Zynq SoC

 

Adam Taylor’s MicroZed Chronicles Part 32: Driving Adafruit RGB NeoPixel LED arrays

 

Adam Taylor’s MicroZed Chronicles Part 31: Systems of Modules, Driving RGB NeoPixel LED arrays

 

 Adam Taylor’s MicroZed Chronicles Part 30: The MicroZed I/O Carrier Card

 

Zynq DMA Part Two – Adam Taylor’s MicroZed Chronicles Part 29

 

The Zynq PS/PL, Part Eight: Zynq DMA – Adam Taylor’s MicroZed Chronicles Part 28  

 

The Zynq PS/PL, Part Seven: Adam Taylor’s MicroZed Chronicles Part 27

 

The Zynq PS/PL, Part Six: Adam Taylor’s MicroZed Chronicles Part 26

 

The Zynq PS/PL, Part Five: Adam Taylor’s MicroZed Chronicles Part 25

 

The Zynq PS/PL, Part Four: Adam Taylor’s MicroZed Chronicles Part 24

 

The Zynq PS/PL, Part Three: Adam Taylor’s MicroZed Chronicles Part 23

 

The Zynq PS/PL, Part Two: Adam Taylor’s MicroZed Chronicles Part 22

 

The Zynq PS/PL, Part One: Adam Taylor’s MicroZed Chronicles Part 21

 

Introduction to the Zynq Triple Timer Counter Part Four: Adam Taylor’s MicroZed Chronicles Part 20

 

Introduction to the Zynq Triple Timer Counter Part Three: Adam Taylor’s MicroZed Chronicles Part 19

 

Introduction to the Zynq Triple Timer Counter Part Two: Adam Taylor’s MicroZed Chronicles Part 18

 

Introduction to the Zynq Triple Timer Counter Part One: Adam Taylor’s MicroZed Chronicles Part 17

 

The Zynq SoC’s Private Watchdog: Adam Taylor’s MicroZed Chronicles Part 16

 

Implementing the Zynq SoC’s Private Timer: Adam Taylor’s MicroZed Chronicles Part 15

 

MicroZed Timers, Clocks and Watchdogs: Adam Taylor’s MicroZed Chronicles Part 14

 

More About MicroZed Interrupts: Adam Taylor’s MicroZed Chronicles Part 13

 

MicroZed Interrupts: Adam Taylor’s MicroZed Chronicles Part 12

 

Using the MicroZed Button for Input: Adam Taylor’s MicroZed Chronicles Part 11

 

Driving the Zynq SoC's GPIO: Adam Taylor’s MicroZed Chronicles Part 10

 

Meet the Zynq MIO: Adam Taylor’s MicroZed Chronicles Part 9

 

MicroZed XADC Software: Adam Taylor’s MicroZed Chronicles Part 8

 

Getting the XADC Running on the MicroZed: Adam Taylor’s MicroZed Chronicles Part 7

 

A Boot Loader for MicroZed. Adam Taylor’s MicroZed Chronicles, Part 6 

 

Figuring out the MicroZed Boot Loader – Adam Taylor’s MicroZed Chronicles, Part 5

 

Running your programs on the MicroZed – Adam Taylor’s MicroZed Chronicles, Part 4

 

Zynq and MicroZed say “Hello World”-- Adam Taylor’s MicroZed Chronicles, Part 3

 

Adam Taylor’s MicroZed Chronicles: Setting the SW Scene

 

Bringing up the Avnet MicroZed with Vivado

 

 

 

 

 

 

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About the Author
  • Be sure to join the Xilinx LinkedIn group to get an update for every new Xcell Daily post! ******************** Steve Leibson is the Director of Strategic Marketing and Business Planning at Xilinx. He started as a system design engineer at HP in the early days of desktop computing, then switched to EDA at Cadnetix, and subsequently became a technical editor for EDN Magazine. He's served as Editor in Chief of EDN Magazine, Embedded Developers Journal, and Microprocessor Report. He has extensive experience in computing, microprocessors, microcontrollers, embedded systems design, design IP, EDA, and programmable logic.