1. Introduction to the ARM mbed Platform– A Hands-on Course
Class 5: Porting mbed
January 13, 2017
Charles J. Lord, PE President, Consultant, Trainer Blue Ridge Advanced Design and Automation

2. This Week’s Agenda
1/9 Peeking Under the mbed Hood 1/10 CMSIS, Hands-On 1/11 mbed Communications and Multitasking 1/12 The mbed Developer Network 1/13 Porting mbed

3. This Week’s Agenda
1/9 Peeking Under the mbed Hood 1/10 CMSIS, Hands-On 1/11 mbed Communications and Multitasking 1/12 The mbed Developer Network 1/13 Porting mbed

4. Putting mbed on Your Hardware
As we have seen, once we pick our chosen Cortex-based development board from the mbed ‘catalog’, all of the necessary HAL and define files are automatically loaded
BUT – what about putting mbed 5.2 on our OWN hardware design?

5. Four Basic Porting Paths
Incorporate an existing demo or development board into your board (the CAD files are often provided for this purpose) Modify I/O pin definitions as needed
Using the HAL and class files from a similar board, manually change each definition from the demo board to your hardware. ** NOT recommended **

6. Four Basic Porting Paths
Use the yotta scripting tool to load in an existing board (“target”) and use the Targets “inherits” and “similarTo” functions to define the new properties.
Use the new mbed HDK (hardware development kit) to create the HAL layer from the schematic.

7. Our Challenge
An industrial controller (vending machine) that is based on the K64 chip
For simplicity, we will use the same variant and package as used on the FRDM board
The circuit has many I/O to read sensors and control motors and solenoids
We don’t use the accelerometer or other features of the FRDM board

8. Other Factors
Our client / customer has specified a form factor for the product that precludes us using the FRDM board with shields (or other daughter boards)
We will also have a remote character LCD and buttons for user interface (no GUI)
We wish to use the features of mbed 5.2

9. Path 1 - Incorporation
We are fortunate to have access to the hardware design of the FRDM-K64 board from the NXP website
A search at nxp.com for “FRDM-K64F schematic” turned up many PDF files and one zip…

10. Design Files

11. Unzip

12. Readme – the files are OrCad

13. Next Steps
Depending on our in-house EDA program, we may need to convert the files or just work in OrCad / Allegro to design our hardware
We need to manually document every pin use change
We will then modify the classes that affect those pins (search tool in IDE can be very helpful!)

14. Path 2 – Write From Scratch
Start with the closest existing board and begin the project
Referring to the mbed manual(s), modify the HAL and CORE modules, plus all classes that are needed for each pin.
This is the most time consuming and error-prone approach – but works

15. Path 3 - yotta
yotta is a tool for building either modules or executables and is used extensively in the mbed community
Yotta is command-line driven and is written in python. It works best on a native linux (or OS X) system but can run in a shell on Windows.

17. There is a Win Installer

18. Targets

19. Yotto and Targets
There are a number of examples on GitHub showing the process
Yotto works directly with your GitHub repositories, both public and private
Yotto is a powerful tool, but there is a definite learning curve
Possible future class

20. Path 4 – mbed HDK
Originally an internal project at ARM, the HDK is being rolled out to users
Only minimal documentation, again on GitHub
Makes use of EAGLE EDA program to design the hardware then compiles the HAL data from the design

21. https://developer.mbed.org/handbook/mbed-HDK

22. https://github.com/ARMmbed/mbed-HDK

23. HDK
The HDK actually resides on the GitHub repository on the previous slide
Documentation is very spartan
Requires the hardware to be laid out in EAGLE – or exported to EAGLE from your regular EDA software
This is the easiest and best approach once you are familiar with the process and familiar with EAGLE…

24. Looking to the Future
Yotta has some nice applications, but runs better in linux
Could use better tutorials – hoping to have a YouTube in the mbed channel soon
The HDK will become more mature over time
Currently planning a CEC class on EAGLE the week of 11/30/17 which will include a day on the HDK

25. This Week’s Agenda
1/9 Peeking Under the mbed Hood 1/10 CMSIS, Hands-On 1/11 mbed Communications and Multitasking 1/12 The mbed Developer Network 1/13 Porting mbed

26. Please stick around as I answer your questions!
Please give me a moment to scroll back through the chat window to find your questions
I will stay on chat as long as it takes to answer!
I am available to answer simple questions or to consult (or offer in-house training for your company)