How to control physical devices with mruby

How to control How to control physical devicesphysical devices

with mrubywith mrubyRubyConf 2013RubyConf 2013

Team YamanekkoTeam YamanekkoYurie Yamane / Masayoshi TakahashiYurie Yamane / Masayoshi Takahashi

Demo

Blinking 4 LEDson STM32F4 Discovery(using Timer)

DEMO (STM32F4 Discovery)● blinking LED

Green on -> Orange on -> Red on -> Blue on -> Green off -> Orange off -> Red off -> Blue off -> ...

Contents● Demo (STM32F4 Discovery)● Introduction● What's mruby● 7 steps to use mruby● Demo (Raspberry Pi)● Another Demo (STM32F4 Discovery)

Who are we?

●やまね　ゆりえ (Yurie Yamane)●高橋征義 (Masayoshi Takahashi)

Who are we?

Team Yamanekko

Independent E-Book Publisher

http://tatsu-zine.com/

Tatsu-zine Publishing Inc.

This session is supported by

http://ruby-no-kai.org/

members of asakusa.rb

Who are we?

●Not professional Embedded programmers– it's our hobby project

●not made e-book reader yet

Our goals

“embedded programming for everyone without hassle”

Our talks

RubyConf2012

Our talks

RubyConf.tw 2012

Our talks

OSDC.tw 2013

Our talks

http://www.flickr.com/photos/igaiga/8564676738/

Ôedo RubyKaigi 03

Embedded is hard??

●small memory●RTOS or no OS●no STDIO●cross compile C/C++/Asm●cross debugger with ICE

Embedded is hard??

●small memory●RTOS or no OS●no STDIO●cross compile C/C++/Asm●cross debugger with ICE

http://mrb.h2so5.net/

What's mruby?

● “yet another implementation of Ruby”–not a new language nor variant

CRuby vs mruby

●mruby is not “an application”●mruby is “a part”

–embedded into other application●webserver, editor, game, ...

–embedded into other systems●robot, router, vending machine, ...

mruby's feature

(1) embeddable(2) configurable(3) pluggable

(1) embeddable

*.rb

C/C++ app

CRuby app mruby app

*.rb(bytecode)

/usr/bin/ruby

libmruby.a

CRuby

/usr/bin/ruby

*.rb (your code)

*.rb (stdlib) Gems

mruby

mruby core

*.rb (stdlib)

*.rb (your code)

C/C++libmruby.a

Bytecode(C String)

mrbgems

Bytecode(C String)

(2) configurable● mruby has many #define macros to configure

– float or double as Float object– using NaN boxing or not– default size of heap, pool, khash, ...

● You can change them at compile time

#define in mrbconf.h● MRB_USE_FLOAT● MRB_INT64● MRB_NAN_BOXING● MRB_ENDIAN_BIG● MRB_FUNCALL_ARGC_MAX● MRB_HEAP_PAGE_SIZE● MRB_USE_IV_SEGLIST● MRB_IVHASH_INIT_SIZE

● MRB_IREP_ARRAY_INIT_SIZE● KHASH_DEFAULT_SIZE● POOL_ALIGNMENT● POOL_PAGE_SIZE● MRB_STR_BUF_MIN_SIZE● MRB_PARSER_BUF_SIZE● ENABLE_DEBUG

(3) pluggable● mruby has mrbgems like RubyGems● mrbgems in C are linked statically● some functions in CRuby are provided as gem– you can choose which is added / removed

standard mrbgems● mrbgems/mruby-array-ext● mrbgems/mruby-enum-ext● mrbgems/mruby-eval● mrbgems/mruby-exit● mrbgems/mruby-fiber● mrbgems/mruby-hash-ext● mrbgems/mruby-math● mrbgems/mruby-numeric-ext● mrbgems/mruby-object-ext● mrbgems/mruby-objectspace

● mrbgems/mruby-print● mrbgems/mruby-proc-ext● mrbgems/mruby-random● mrbgems/mruby-range-ext● mrbgems/mruby-sprintf● mrbgems/mruby-string-ext● mrbgems/mruby-struct● mrbgems/mruby-symbol-ext● mrbgems/mruby-time● mrbgems/mruby-toplevel-ext

you can remove them all

7 steps to use mruby ● choose your target board● setup development environments● write application● cross build● transfer binary to the board● cross debugging● it works!


Our targets crieteria● easy to buy around the world

– some are hard outside Japan :(● don't use apps depending on OSs or environments

– FLOSS tools are better● a bit large memory that mruby can run on

– > 64KB is MUST, > 1MB is BETTER

(1) STM32F4 Discovery● ARM (Cortex M4)● 1MB Flash, 192KB RAM● 8LEDs, 2Buttons, MEMS Accelerometer etc.

● on board STLINK

http://www.st.com/web/catalog/tools/FM116/SC959/SS1532/PF252419

(2) Raspberry Pi● ARM (arm1176jzf-s)● 256/512MB RAM● SD card● 700mA (3.5W)● JTAG

ARM11 & Cortex-M4

Raspberry Pi

STM32F4

http://www.emcu.it/CortexFamily/CortexFamily.html

**NOTICE**

● We do not use OS on Raspberry Pi– no raspbian nor other Linux/Unix

Why no OS (bare metal)?● same as STM32F4 Discovery

–STM32F4 Discovery is used without OS● We want to use Raspberry Pi like MCU, not PC

– just as MCU with HUGE memory–If using Linux, even CRuby can work on Raspberry Pi :-/

● Bare metal programming is fun :-)

bare metal RasPi Programming

● dwelch67's github repos is incredibly useful– https://github.com/dwelch67/raspberrypi– everything we need is here

STM32F4d architecture

CortexMCU

Systicktimer

NVICinterrupt controller

otherperipheralsM

CU

Peripheral Register & Interrupt Vector Definitions

Core PeripheralFunctions

Device PeripheralFunctions

mruby core (in c)

mrbgems for STM32F4 Discovery

Ruby code (*.rb → bytecode)

CMSI

Sap

ps

libc (newlib), syscalls

libmruby.amain(c)

Raspberry Pi architecture

ARM11MCU

Timer Other BCM2385peripheralsSo

C

mruby core

mrbgems for Raspberry Pi

Ruby code (*.rb → bytecode)

apps

libc (newlib), syscalls

vectors.s

libmruby.a


Our Development Environment

● Cross Compiler: GNU tool chain● IDE: Eclipse CDT + our original plugin● Debugging :

– STLINK (for STM32F4d)– JTAG (for RasPi)

cross compiler for STM32F4GNU Tools for ARM Embedded Processors (https://launchpad.net/gcc-arm-embedded)

cross compiler for RasPi● 'GNU Tools for ARM Embedded Processors' is...

– “1. ARM11 is not our primary targets, so those tools are not tested on such targets.”

– “Thus I don't recommend this tool chain for Raspberry Pi.”https://answers.launchpad.net/gcc-arm-embedded/+question/227876

● So we use GNU Tools built by our own.https://github.com/dwelch67/build_gcc/blob/master/build_arm

PC

How to debug with STM32F4d

STM32F4d

EclipseSTLINK stlink

USB cable

stlink: https://github.com/texane/stlink

gdbfor arm

arm-none-eabi-gdb

PC

How to debug with RasPi

RasPi

USB and JTAG cable

OpenOCD: http://openocd.sf.net/armjtag: https://github.com/dwelch67/raspberrypi/tree/master/armjtag

Eclipsearmjtag OpenOCD gdbfor arm

arm-none-eabi-gdb

JTAG debugger (hardware)

● connect ARM via USB

https://www.olimex.com/Products/ARM/JTAG/ARM-USB-TINY-H/

ARM-USB-TINY-H

JTAG debugger (hardware)

● connect JTAG cable

and RasPi● Use 6pins only (and GND)

https://www.olimex.com/Products/ARM/_resources/arm-jtag-layout.gif

JTAG debugger (software)

● You can do fash programming and GDB debugging with OpenOCD.

http://openocd.sourceforge.net/

armjtag

https://github.com/dwelch67/raspberrypi/tree/master/armjtag

“an alternate bootloader”“The ARM11 on the Raspberry Pi has a jtag based debug port for software development.”

are you tired?


write application

● write Ruby code● write mrbgems● write C code

Including Ruby code in mruby

● As source code of Ruby– Human readable

● As Byte code– Machine readable




hello world in mruby (1)#include <stdlib.h>#include <stdio.h>#include <mruby.h>#include <mruby/compile.h>

int main(void){ mrb_state *mrb = mrb_open(); char code[] = "p 'hello world!'"; mrb_load_string(mrb, code); mrb_close(mrb); return 0;}

hello world in mruby (1)

mrb_state *mrb = mrb_open(); char code[] = "p 'hello world!'"; mrb_load_string(mrb, code); mrb_close(mrb);




hello world in mruby (2) mrb_state *mrb = mrb_open();

const uint8_t bcode[] = { 0x52,0x49,0x54,0x45,0x30,0x30,0x30, (… byte byte byte …) 0x00,0x00,0x00,0x00,0x08, };

mrb_load_irep(mrb, bcode); mrb_close(mrb);

hello world in mruby (2)$ cat hello.rbp 'hello world!'$ ./bin/mrbc -Bbcode hello.rb$ cat hello.c#include <stdint.h>const uint8_t foo[] = {0x52,0x49,0x54,0x45,0x30,0x30,0x30,0x31,0xb9,0x71,0x00,0x00,0x00,0x65,0x4d,0x41,(…)0x00,0x00,0x00,0x00,0x08,};$

mrb_open

Create and initialize new mruby VM

Usage:

mrb_state *mrb = mrb_open();

mrb_close

release mruby VM

Usage:

mrb_close(mrb);

mrb_load_irep

load mruby bytecode and execute.

Usage:

mrb_load_irep(mrb, bcode);

mruby API

In include/mruby.hand include/mruby/*.h

※all API has mrb_state at 1st arg.

ex. mrb_load_string(mrb, code);

mrbgems

● “mruby gems” by bovi● library packaging system like RubyGems

● static linked with compile time

mrbgem.rake

MRuby::Gem::Specification.new(

'mruby-rs-led') do |spec|

spec.license = 'MIT'

spec.authors = 'yamanekko'

end

minirake

mruby has minirake full source– minimal rake clone by masuidrive– you do not have to install rake even if using Ruby 1.8

● mrbgems and mruby itself are built by minirake

Why (mini)rake● old mruby used CMake● but mruby build system became complex

– build mrbgems (Ruby and C)– get source code from github– support gem bundle (gembox)

● we want to write them in Ruby

build_config.rb

● Ruby (not mruby) script– Execute in host machine at building time

● DSL to build mruby● Load from Rakefile

Default (minimal) build_config.rb

MRuby::Build.new do |conf|

toolchain :gcc

conf.gembox 'default'

end

DEMO (Raspberry Pi)● blinking LED (like STM32F4 Discovery)

Green on -> Orange on -> Red on -> Blue on ->Green off -> Orange off -> Red off -> Blue off

Ruby Code (init)

Ruby Code (blink)


demousing Eclipse

Install MrubyTools plugins

Install MrubyTools plugins

create mruby project● cloned from https://github.com/mruby/mruby

CREATE CUSTOM mrbgems● create new mrbgem to control STM32F4-Discovery's LED

from ruby

generated mrbgem filesmrbgem wizard can create necessary files, directory structure and template files

generated mrbgem template

add code for Led class

← class

← constants

↑ methods

build_config.rb for RasPi

libmruby.a generated

CREATE RasPi'S PROJECT● Create new C project● Create new files

– demo.c– syscalls.c– vectors.s– memmap– makefile–

create app project

Write ruby code● Insert “beginning tag” and “ending tag”● write ruby code between beginning tag and ending tag● Two ways to embed ruby code1.Use menu bar

2.Use tool bar

Insert ruby code in .c file

Insert .rb file name in .c file

/* <ruby->

... <-ruby> */

/* <rubyfile->

aaa.rb <-rubyfile> */

before conversion

execute mrbc wrapper

after conversion

OpenOCD uses gdb and telnet

openocd

telnet

gdbEclipse

RasPi

port 3333

port 4444

command Interface

openocd as external tool

call openocd

OpenOCD log in Eclipse

connect OpenOCD via telnet

setting gdb command

Another Demo: blinking LED & MEMS Accelerometer

using STM32F4d

Push Button

Push Button

Power ON

blinkingmode

tilt sensormode

switching 2 modes by pushing button

Tilt sensor in STM32F4d

● using 3-axis MEMS accelerometer in STM32F4 Discovery– only use 2 axis (X and Y)– LED show which side is downward

Another Demo: blinking LED & MEMS Accelerometer

using STM32F4d

Push Button

Push Button

Power ON

blinkingmode

tilt sensormode

switching 2 modes by pushing button

future issues● Ruby source level debugger

● support bytecodes generated by mrbc● more mrbgem samples

Our Links● source code

● http://github.com/yamanekko/mruby/tree/rubyconf● Eclipse Plugin download site (for Eclipse)

– http://yamanekko.github.io/mruby-tools-EclipsePlugin● This slide

● http://slideshare.net/yamanekko/rubyconf2013

Useful mruby linksmruby repos: https://github.com/mruby/mrubymruby.sh: http://blog.mruby.sh/Introduction to Lightweight Ruby "mruby" (by Toshiba): http://www.tjsys.co.jp/page.jsp?id=3059

mruby code search: http://mruby-code-search.ongaeshi.me/ngx_mruby: http://matsumoto-r.github.io/ngx_mruby/webruby: https://github.com/xxuejie/webrubymobiruby: http://mobiruby.org/

Thanks!Happy mruby Hacking!

special thanks to: @tenderlove and @_zzak

Technology

How to control physical devices with mruby