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  • Author Author: neilk
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Adventures with the Raspberry Pi pico - part 2

neilk
Introduction

 

At the end of my previous blog:  Adventures with the Raspberry Pi pico - part 1

 

I said:

 

"Next Step:"

"Learn how to modify the blink source file - to blink2 -  build/compile it and then flash the pico with the modified file."

 

In fact, I need to understand what I've actually done - I was just following someone else's instructions. Many people reading this will already know, but maybe some won't! I hope it helps them!

 

Although I don't fully understand them, all the steps associated with downloading and setting up all the software will stand - that only has to be done once (I hope), although I will have to repeat it, if I decide to install all this on my desktop PC.

 

I'm going to start my understanding process at section 7 of my previous blog, which is taken from:

 

https://datasheets.raspberrypi.org/pico/getting-started-with-pico.pdf 

 

Has been revised and sections renumbered since this blog was written.

 

Note, this assumes that C:\Users\pico\Downloads has already been created

 

8.2.2. EDIT 9.2.2 Getting the SDK and examples

 

C:\Users\pico\Downloads> git clone -b master https://github.com/raspberrypi/pico-sdk.git

C:\Users\pico\Downloads> cd pico-sdk

C:\Users\pico\Downloads\pico-sdk> git submodule update --init

C:\Users\pico\Downloads\pico-sdk> cd ..

C:\Users\pico\Downloads> git clone -b master https://github.com/raspberrypi/pico-examples.git

 

My questions are:

 

  1. What does  git clone -b master https://github.com/raspberrypi/pico-sdk.git  do?

  2. What does  git submodule update --init  do?
  3. What does git clone -b master https://github.com/raspberrypi/pico-examples.git  do?

 

Taking each of these in turn:

 

1. What does  git clone -b master https://github.com/raspberrypi/pico-sdk.git  do?

 

I think it means what it says - ie clone the pico-sdk from github to my device. I assume that by default, it will create the clone in a new sub-folder - .../pico-sdk/.

But what does "-b master" mean?

 

Looking at the git documentation:  https://git-scm.com/docs/git-clone  we find:

 

image

 

That means that we want to clone the master branch, rather than any other branch that the remote HEAD is pointing to.

Below is a screen shot from the remote repository - https://github.com/raspberrypi/pico-sdk

image

This shows a master and 6 branches, with master set as the default. Including "-b master"  seems to be "belt and braces", which, of course, is ALWAYS good, fail-safe, practice.

Taking my understanding further, I opened a command window in admistrator mode and created a new folder below .. \pico\ :   C:\Users\pico\Download_test .

I then ran the command:

C:\Users\pico\Download_test> git clone -b master https://github.com/raspberrypi/pico-sdk.git

Below is screenshot from Windows File Manager of the structures created by that command:image

Apart from the presence of a folder called .git, this looks exactly like the screenshot of the remote repository. This was to be expected.

 

2. What does  git submodule update --init  do?

 

I looked at the documentation and it meant nothing to me image

I ran the command :

C:\Users\pico\Download_test\pico-sdk> git submodule update --init

And got the following result:

image

So, 'tinyusb', which belongs at a higher level - raspberrypi - is also registered at the level of the pico and needs to be cloned and added in.

I don't understand what this means - it's my first exposure to git! Perhaps if an expert reads this, he/she could explain it to me, please.

 

3. What does git clone -b master https://github.com/raspberrypi/pico-examples.git  do?

 

Fairly obviously, I think, this is going to clone the contents of pico-examples to my device.

I ran the command:

C:\Users\pico\Download_test> git clone -b master https://github.com/raspberrypi/pico-examples.git

Without repeating screenshots, I can say that I now have a clone of pico-examples which looks exactly like the contents of the remote repository, except that it also has a .git folder.

 

8.2.3. Building "Hello World" from the Command Line

This is misleading, as and I discussed in my previous blog - it builds ALL of the examples!

The commands I don't understand are:

C:\Users\pico\Downloads\pico-examples\build> cmake -G "NMake Makefiles" ..

Which sets somethings up for all the examples.

 

EDIT - something went wrong and the last part of the document wasn't saved!!!

 

C:\Users\pico\Downloads\pico-examples\build> nmake

Which builds all the examples.

 

I tried to find some information on cmake, NMake, Makefiles, but couldn't find anything useful!

 

I haven't understood everything, but I've had enough!

 

Next part will be Visual Studio proper!