From Web Developer To Hardware Developer

(1+2+3+…10 )

10

(1+2+3+..16) >> 4

1000000.10

= 100000

100000.010

= 100000

82

=1000.

10=

100.0 = 4

Workflow

Let’s Make A Change In Ruby

New Features Web

1. Cucumber / UI

2. Write a presenter / controller

3. Then maybe you write a model

4. Hopefully all tests pass

Start with a small test

How The Web Works

apache/nginx

Application Runtime

Your Code

Database

IIS

.NET Framework

Your Code

SqlServer

How Embedded Works

Event Loop

Interrupts are fast

static uint8_t handler_flag = FALSE;

__interrupt void handler(void){handler_flag = TRUE;}

static uint8_t handler_flag = FALSE;

__interrupt void handler(void){handler_flag = TRUE;}

void main(void){while(1){if (handler_flag){// do some stuffhandler_flag = FALSE;

}}}

Inputs

Blocking Code

apache/nginx

Application Runtime

Your Code

Database

void main(void){while(1){while(databaseWri

te){//Wait

}}}

Event Loop

__interrupt void write_callback(void){write_finished = TRUE;}

while(1){start_write();if(write_finished){// do something

}}}

Frameworks/Libraries

• Rails

• Bundler

• Cocoapods

• Pip/ez_install ?

No Training WheelsController

Model ViewConductor

Model Hardware

TDD and Embedded

• RSpec

• MiniTest

• Cucumber

• XCTest

https://pragprog.com/book/jgade/test-driven-development-for-embedded-c

Testing Off Target

It’s just memory

Conductor

Model Hardware

Conductor

Model Hardware Mock Hardware*

* Software Version Of Hardware

static uint8_t button_mock = 0x0;

void test_button_is_pressed(void){button_mock = 0x0;TEST_ASSERT_EQUAL(isButtonPressed(&button_mock), 1);}

int isButtonPressed(uint8_t *button_ptr){//some logic around button}

0

Finding Failures

Handling Memory

void do_some_process(uint8_t arg1, uint8_t arg2);

4 bytes

RTOS

Scheduler

Job 1

Job 2

Job 3

Job 4

Job 5

Scheduler

Job 1

Job 2

Job 3

Job 4

Job 5

Scheduler

Job 1

Job 2

Job 3

Job 4

Job 5

Scheduler

Job 1

Job 2

Job 3

Job 4

Job 5

Scheduler

Job 1

Job 2

Job 3

Job 4

Job 5

Scheduler

Job 1

Job 2

Job 3

Job 4

Job 5

Scheduler

Job 1

Job 2

Job 3

Job 4

Job 5

Releases

$ git push origin masterCounting objects: 6, done.Delta compression using up to 4 threads.Compressing objects: 100% (5/5), done.Writing objects: 100% (6/6), 1.90 KiB | 0 bytes/s, done.Total 6 (delta 1), reused 0 (delta 0)To git@github.com:alexshenoy/my_project.git + 93aa517...334aee4 master -> master

• Compile Code

• Transfer it to a supplier

• Issue a change request to the supplier

• Ship new products

Where To Get Started

• Arduino

• SparkFun - SparkCore

• AdaFruit

Alex Shenoy@alexshenoy

http://alexshenoy.com/