[Tutorial][Beginner]1."Hello World!" - making your first program


#1

1. The basic “Hello World!” program

In this lesson we will learn the basics of how to make your first program on Pokitto.

The program will put a simple text “Hello World!” on the Pokitto screen.

We will be making the program in the super-simple mbed online tools!

2. Welcome to the “Mbed” ecosystem!

“Mbed” stands for “embedded”. Embedded programming means programming the little chips called microcontrollers that are used in things like 3D-printers, robot vacuum cleaners, RC-drones etc. They are kind of “tiny computers” that can do awesome things.

Pokitto is an mbed device and can be programmed in the mbed ecosystem!

3. Getting yourself an Mbed account

Signing up as an Mbed user is free. Just go to the [signup page at os.mbed.com] (https://os.mbed.com/account/login/?next=/) to begin making yourself an Mbed account.

All of your coding and work will be done inside this account - you do not need to install anything on your own computer!

4. Adding the Pokitto chip (LPC11U68) as target to your account

Before you can write code for Pokitto, the Mbed online compiler needs to know what target device you are planning to use your program on.

For this step, make sure you are now logged in to the Mbed site!

  1. go to LPCXpresso11U68 home page
  2. press Add to your Mbed Compiler button

5. Open the “Hello World!” example program in the online compiler

Pokitto Community has its own “team” on Mbed. You can find our page here.

On that page, you will find the “HelloWorld” example program. Click the link.

Now you are on the “HelloWorld” program page. Click the “Import into Compiler” button. This will open up the “Hello World” example program in the online compiler.

When the window opens, just press “Import”

6. You are ready to program!

Now you are in the Mbed online compiler and the “Hello World” example program is open.

What you see in front of you is a quite simple but very capable online editor, that allows you to edit the code as text, create new programs, add, delete and rename files and folders inside your project.

In the middle is the main.cpp file that contains the main function of your program.

Now you can, for example, change the text “Hello World!” on line 9 to whatever you want. Just remember that text in the C++ language that Pokitto uses always needs to start with a single quotation mark (") and end in another quotation mark. Also, every line of code needs to end in a semicolon (;).

When you are ready, press the “Compile” button to create your program. It will come to you as a downloadable .bin (binary) file, that you can put on your Pokitto.

For video instructions, please look at: [Start]2.Writing your first Pokitto program in the mbed online ecosystem:


[Game]Racers [wip]
Ball Fall Down (WIP)
#2

seems to be a problem

Error: “PokittoLib/mbed-pokitto/targets/cmsis/TARGET_NXP/TARGET_LPC11U6X/TOOLCHAIN_ARM_MICRO/TARGET_LPC11U68/LPC11U68.sct”, line 3 (column 9): Error: L6235E: More than one section matches selector - cannot all be FIRST/LAST.

Error: Not enough information to list the image map.


#3

Thanks, will fix it right away

EDIT: can not replicate issue


#4

I am unable to replicate issue. If program contains PokittoLib from https://os.mbed.com/users/Pokitto/code/PokittoLib/ , every one of them compiles without issues.

Please check you do not have some sort of local copy and check that Pokitto/PokittoLib is where the library is coming from.

EDIT:

Could not replicate even with a second non-admin account I keep for testing


#5

my bad i still had the mbed-src in there

do need to cover that you need to make a my_settings.h file


#6

Just wanted to share a quick error we had in case someone else gets a similar error. After importing the project you must ensure that LPCXpresso11U68 is the selected platform. I had a different device selected from a different project of mine a long time ago which I had forgotten about. So we had a bunch of compiler errors.

So in step 6, it’s a good idea to ensure you have LPCXpresso11U68 listed on the top right as shown in jonne’s image. If not, click on it and you should be able to select it as the target if you added it as a compiler option correctly in steps 1-2.


#7

Finally picked up a beginners C++ book :wink:

Will hopefully be joining the rest of you with programming skills soon-ish :innocent:


#8

I have tried the steps above but only receive a black screen when I compile and load the program onto the pokitto using either the USB card or directly in program mode.


#9

Does the Hello World project work for anybody else? I get the same as @TigerJ, but I assumed I’d broken it somehow. I think it broke with a library update.


#10

I have done heavy editing so it is possible. I will check it out


#11

I am not able to replicate this issue. Could you try this binary ? I just made it in the mbed compiler and it works 100% for me.

HelloWorld_LPC11U68.bin (28.6 KB)


#12

Still a black screen. When I load other programs that came on the usb card it works fine. Just the hello world program seems to be a black screen. I added it to the usb card. I used windows for this after reading a few posts about a white screen and special mac loaders.


#13

Ok. I’m trying to understand where this problem is coming from.

  1. when do you get the black screen?
    a) no pokitto logo at all
    b) after pokitto logo (no sound level selection)
    c) after sound level selection screen

  2. please flash the binary below to your pokitto, then try the hello world again

  • any difference?

start.bin (256 KB)


#14

The hello world results in B, after pokitto logo, no sound selection.

the start.bin gives me the eyes and mouth animating on the screen. (fully functional)

after the start.bin I receive the hello world and IT WORKS! yay

(what happened?)


#15

The Eeprom (where settings are) was uninitialized and contained random numbers. Start.bin forces settings in place.

I now know exactly where the problem is, thank you very much for your help