This is a very simple guide, reviewing the steps required to get Blinky working on an Mbed OS platform.

Mbed OS Blinky

This example shows the use of a DigitalOut object to represent an LED and use of the nonblocking Thread::wait() call. Using nonblocking calls is good practice because Mbed OS can schedule and run other threads while the first thread is waiting.

Building this example

Building with Arm Mbed CLI

To use Mbed CLI to build this example, follow the instructions in the documentation. The instructions here relate to using the Arm Online Compiler.

To use the Online Compiler, import this code into the Online Compiler, and select your platform from the top right. Compile the code using the compile button, load it onto your board and press the reset button on the board. The code will run on the board, and you will see the LED blink.

You can find more instructions for using the Mbed Online Compiler in the documentation.

README.md

Committer:
mbed_official
Date:
5 months ago
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File content as of revision 82:abf1b1785bd7:

# Getting started example for Mbed OS

This guide reviews the steps required to get Blinky with the addition of dynamic OS statistics working on an Mbed OS platform.

Please install [mbed CLI](https://github.com/ARMmbed/mbed-cli#installing-mbed-cli).

## Import the example application

From the command-line, import the example:

```
mbed import mbed-os-example-blinky
cd mbed-os-example-blinky
```

### Now compile

Invoke `mbed compile`, and specify the name of your platform and your favorite toolchain (`GCC_ARM`, `ARM`, `IAR`). For example, for the ARM Compiler 5:

```
mbed compile -m K64F -t ARM
```

Your PC may take a few minutes to compile your code. At the end, you see the following result:

```
[snip]
+----------------------------+-------+-------+------+
| Module             |     .text |    .data |     .bss |
|--------------------|-----------|----------|----------|
| [fill]             |    98(+0) |    0(+0) | 2211(+0) |
| [lib]/c.a          | 27835(+0) | 2472(+0) |   89(+0) |
| [lib]/gcc.a        |  3168(+0) |    0(+0) |    0(+0) |
| [lib]/misc         |   248(+0) |    8(+0) |   28(+0) |
| [lib]/nosys.a      |    32(+0) |    0(+0) |    0(+0) |
| main.o             |   924(+0) |    0(+0) |   12(+0) |
| mbed-os/components |   134(+0) |    0(+0) |    0(+0) |
| mbed-os/drivers    |    56(+0) |    0(+0) |    0(+0) |
| mbed-os/features   |    42(+0) |    0(+0) |  184(+0) |
| mbed-os/hal        |  2087(+0) |    8(+0) |  152(+0) |
| mbed-os/platform   |  3633(+0) |  260(+0) |  209(+0) |
| mbed-os/rtos       |  9370(+0) |  168(+0) | 6053(+0) |
| mbed-os/targets    |  9536(+0) |   12(+0) |  382(+0) |
| Subtotals          | 57163(+0) | 2928(+0) | 9320(+0) |
Total Static RAM memory (data + bss): 12248(+0) bytes
Total Flash memory (text + data): 60091(+0) bytes

Image: ./BUILD/K64F/GCC_ARM/mbed-os-example-blinky.bin
```

### Program your board

1. Connect your mbed device to the computer over USB.
1. Copy the binary file to the mbed device.
1. Press the reset button to start the program.

The LED on your platform turns on and off. The main thread will additionally take a snapshot of the device's runtime statistics and display it over serial to your PC. The snapshot includes:

* System Information:
    * Mbed OS Version: Will currently default to 999999
    * Compiler ID
        * ARM = 1
        * GCC_ARM = 2
        * IAR = 3
    * [CPUID Register Information](#cpuid-register-information)
    * [Compiler Version](#compiler-version)
* CPU Statistics
    * Percentage of runtime that the device has spent awake versus in sleep
* Heap Statistics
    * Current heap size
    * Max heap size which refers to the largest the heap has grown to
* Thread Statistics
    * Provides information on all running threads in the OS including
        * Thread ID
        * Thread Name
        * Thread State
        * Thread Priority
        * Thread Stack Size
        * Thread Stack Space

#### Compiler Version

| Compiler | Version Layout |
| -------- | -------------- |
| ARM      | PVVbbbb (P = Major; VV = Minor; bbbb = build number) |
| GCC      | VVRRPP  (VV = Version; RR = Revision; PP = Patch)    |
| IAR      | VRRRPPP (V = Version; RRR = Revision; PPP = Patch)   |

#### CPUID Register Information

| Bit Field | Field Description | Values |
| --------- | ----------------- | ------ |
|[31:24]    | Implementer       | 0x41 = ARM |
|[23:20]    | Variant           | Major revision 0x0  =  Revision 0 |
|[19:16]    | Architecture      | 0xC  = Baseline Architecture |
|           |                   | 0xF  = Constant (Mainline Architecture) |
|[15:4]     | Part Number       | 0xC20 =  Cortex-M0 |
|           |                   | 0xC60 = Cortex-M0+ |
|           |                   | 0xC23 = Cortex-M3  |
|           |                   | 0xC24 = Cortex-M4  |
|           |                   | 0xC27 = Cortex-M7  |
|           |                   | 0xD20 = Cortex-M23 |
|           |                   | 0xD21 = Cortex-M33 |
|[3:0]      | Revision          | Minor revision: 0x1 = Patch 1 |



You can view individual examples and additional API information of the statistics collection tools at the bottom of the page in the [related links section](#related-links).


### Output

To view the serial output you can use any terminal client of your choosing such as [PuTTY](http://www.putty.org/) or [CoolTerm](http://freeware.the-meiers.org/).

The default baud rate for this application is set to `115200` and may be modified in the `mbed_app.json` file.

You can find more information on the Mbed OS configuration tools and serail communication in Mbed OS in the related [related links section](#related-links).

The output should contain the following block transmitted at the blinking LED frequency (actual values may vary depending on your target, build profile, and toolchain):

```
=============================== SYSTEM INFO  ================================
Mbed OS Version: 999999
CPU ID: 0x410fc241
Compiler ID: 2
Compiler Version: 60300
RAM0: Start 0x20000000 Size: 0x30000
RAM1: Start 0x1fff0000 Size: 0x10000
ROM0: Start 0x0 Size: 0x100000
================= CPU STATS =================
Idle: 98% Usage: 2%
================ HEAP STATS =================
Current heap: 1096
Max heap size: 1096
================ THREAD STATS ===============
ID: 0x20001eac
Name: main_thread
State: 2
Priority: 24
Stack Size: 4096
Stack Space: 3296

ID: 0x20000f5c
Name: idle_thread
State: 1
Priority: 1
Stack Size: 512
Stack Space: 352

ID: 0x20000f18
Name: timer_thread
State: 3
Priority: 40
Stack Size: 768
Stack Space: 664

```

## Troubleshooting

If you have problems, you can review the [documentation](https://os.mbed.com/docs/latest/tutorials/debugging.html) for suggestions on what could be wrong and how to fix it.

## Related Links

* [Mbed OS Stats API](https://os.mbed.com/docs/latest/apis/mbed-statistics.html)
* [Mbed OS Configuration](https://os.mbed.com/docs/latest/reference/configuration.html)
* [Mbed OS Serial Communication](https://os.mbed.com/docs/latest/tutorials/serial-communication.html)