Hopper on Raspberry Pi Pico

Hopper is a modern semi-colon and curly brace language designed for small platforms like microcontrollers and the 6502. It has reference types like strings, lists and dictionaries and a managed heap (garbage collection). It is a bit like C# or Java but without classes.

I have another instructional project explaining how to get the development environment up and running on Windows. Once you've done that, this instructional project explains how to get Hopper up and running on your Raspberry Pi Pico or Pico W.

I'm assuming you've got the repo from GitHub cloned and we can go straight into the Hopper environment...

Portable Runtime - Optional

The runtime for microcontrollers is written in Hopper. It can be easily tested and worked on in the Hopper environment on Windows. I have a tool that translates Hopper to C which is used to take this code to other platforms like the Arduino platform.

I have a YouTube video walking through how the portable Hopper runtime is built but this isn't required to just get up and running. It would be useful if you wanted to modify it though: Portable Runtime

Using the Arduino IDE

We use the Arduino IDE to get our Hopper runtime installed on the Raspberry Pi Pico. I won't explain how to setup the Arduino IDE in detail since there is so much material online about that already. This is a useful link though:

https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json

This is the URL to add to the "Additional boards manager URLs" under Files | Preferences in the Arduino IDE:

From the repo that you cloned from GitHub in the instructions for getting up and running on Windows, go to the /Runtimes/Arduino folder. Copy the HopperPortable subfolder to wherever you keep your Arduino projects (the Arduino IDE likes projects to be in a folder the same name as the .ino source file with no spaces in the names). Open the.ino file in the Arduino IDE (currently named HopperPortableV2.ino).

• From Tools | Boards | Raspberry Pi Pico / RP2040... choose your board (probably a Pi Pico or Pi Pico W).
• From Tools | Ports select the COM port that your board is on
• Other important options on the Tools menu once you have your board selected are Flash Size and Optimize. We choose "Fast" for Optimize and 1MB Sketch, 1MB FS for these settings:

• <ctrl><U> to compile and upload to your device

That's it.

Be careful not to have the Arduino Serial Console open when you try to connect to the Pi Pico using Hopper : only one client can use the serial interface at a time. Better to just close the Arduino IDE once you've uploaded the runtime to your device since we won't be needing it anymore.

First Hopper Program

The Hopper repo includes a /Source folder. All Hopper source on the planet is included under this folder. This includes interesting Hopper projects like the compiler, the optimizer, the debugger and the editor/IDE.

There is also a /Source/Samples folder:

Open Blink.hs in the IDE:

Make sure the option to Generate IHex is selected:

Generate IHex makes the CODEGEN part of the toolchain convert the usual Hopper.hexe binary into an Intel HEX version that we use to transfer the program across the serial port to our device.

<F7> to build. You should see a success message in the status bar:

<F5> to launch the debugger and upload the Intel HEX file to your Pi Pico. You'll know you are in the debugger because the title bar changes from blue (editor) to green (debugger):

<F5> again to run the program in the debugger. (<ctrl><C> to break in the debugger.

If you run without the debugger, <ctrl><F5>, then you cannot break using <ctrl><C> and, with a program like blink, that means it will run forever and not be stopable without restarting the Hopper environment (not a disaster since everything is saved but worth knowing).

Hack Alert

Note: although Hopper is capable of enumerating all your COM ports so that we could select a specific port, neither the Debugger nor the Monitor currently do this. I noticed that, at least in my environment, the currently connected microcontroller is always on the latest COM port (the one with the biggest number) and we just connect to that. Massive assumption but it seems to work for now. Obviously that will need to be improved ..

What next?

My YouTube channel has the following playlists:

Hopper Language : introductory tutorial style videos walking through and explaining features of the Hopper language. Applies to Hopper on all platforms.

Hopper on Microcontrollers : demonstrations of Hopper runinng on microcontrollers, mostly on the Raspberry Pi Pico.

Hopper Internals : longer and more in-depth videos describing what's under the hood, why things are the way they are, and how it was made.

Hopper on 6502 : a modern semicolon and curly brace language with garbage collected heap running on an 8 bit CPU!

Subscribe to the YouTube channel and/or follow me on Hackster to get the latest developments. There is a lot still to be done and this way you'll know when key milestones are hit.