Text
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Firmware Programming
with mruby/c
HASUMI Hitoshi
Monstar Lab, Matsue office
2018/6/1
RubyKaigi2018@Sendai International Center
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before starting,
assumed audience
people who want to make IoT with
Ruby
people who have never touched
mruby/c
people who did only tutorials of
mruby/c
people who love Sake
what this talk doesn't mention
microcontroller itself and
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recommended book about
microcontroller
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recommended tutorial
http://www.s-itoc.jp/activity/research/
mrubyc/mrubyc_tutorial/
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agenda
terminology
about my IoT project
mruby and mruby/c
how does mruby/c work
debugging
actual source code of my project
development environment
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terminology
mruby/c
I say エムルビーシー[emurubi:ʃí:] in
this talk
microcontroller = マイコン[maikon]
small computer contains CPU,
memory and programmable I/O
peripherals
in this talk, microcontroller is
distinguished from single board
computer like Raspberry Pi.
RasPi is rich, microcontroller is poor
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terminology
RTOS
Real-time OS. usually used for
microcontroller. but we won't use it
task
almost equivalent to `thread` in
linux. we say `task` in
microcontroller world
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terminology
旭日酒造(asahi-shuzo)
one of the best Japanese Sake
brewery
I also call the brewery asahi-san
asahi-san and I make IoT system
using mruby/c
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terminology (IMO)
旭酒造(asahi-shuzo), yamaguchi: 獺祭
(dassai). fruity, aromatic and sweet
朝日酒造(asahi-shuzo), niigata: 久保田
(kubota). clear, dry and sharp
朝日酒造(asahi-shuzo), fukui: I don't
know at all...
旭日酒造(asahi-shuzo), shimane: 十旭
日(juji-asahi). tasteful, mature with
years and good for お燗(warmed style)
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why microcontroller?
(rather than single board computer)
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why microcontroller?
it starts immediately right after
plugged in
end users, brewery workers in my
case, can use simply
you can narrow security issue list
many a malware aims at linux or
windows platform as a target
you don't need to consider
unnecessary deamon
you don't need to do `apt upgrade`
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why microcontroller?
low energy
rarely overheated
many choices of power supply
mass production
you can choose appropriate chipset
(number of GPIOs, memory size,
etc.) for your application
cost advantage for parts supply and
subcontractor manufacturing
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which microcontroller?
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which microcontroller?
CYPRESS PSoC5LP
32-bit Arm Cortex-M3 CPU
Flash/SRAM: 256KB/64KB
package: 68-pin QFN, 99-pin WLCSP,
100-pin TQFP
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which microcontroller?
PSoC5LP Prototyping Kit
for prototyping and small production
you can purchase with 秋月電子通商
(akizukidenshi.com)
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mruby/c works on only PSoC5LP?
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mruby/c works on only PSoC5LP?
yes and no
the number of microcontroller on
which mruby/c runs is increasing
PSoC5LP is the most recommended
one. because it has a good example,
my project
PSoC5LP is very resonable to develop
IoT product especially for mass
production
IMO, the mruby/c core team made
the right choice
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about my IoT project
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about my IoT project
IoT system for asahi-san
delivered to actual brew work in
January 2018
devices post temperature of Sake
materials in brewing, surrounding
temperature and humidity to server
data is displayed on smartphone app
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about my IoT project
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about my IoT project
what were difficult about mruby/c?
we can neither do step execution nor
look into appropriate memory
address of mruby/c's variables
so many factors to be trouble in IoT
hard to find why the application
doesn't work well
mruby/c is growing
bugs, lack of docs and examples
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about my IoT project
so, is mruby/c bad?
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about my IoT project
so, is mruby/c bad? - NO
IoT at work makes you hurry
you have to go alternately to dark
10℃ storage cellar and humid 35℃
manufacturing room
brewery workers run around
you have to amend your firmware
with your small laptop in 10 minutes
you will thank Ruby's
descriptiveness and agility
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today's demo
CO 2 concentration
400ppm : atmospheric
1000ppm : your programming
speed decreases
1500ppm : tomatoes🍅 may grow
well
> 2000ppm : sleepy, headache
> 40000ppm : 💀
HD = humidity deficit = 飽差
3~6g : tomatoes🍅 grow well
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today's demo
prev page's graph shows CO2 of
room I stayed last night
CO2 concentration went up though 24
hour ventilation is mandatory
it is terrible that CO2 reached
2000ppm when I should have wake
up, isn't it?!
the device will measure while I talk
today. so I prove that it is due to CO2
if someone slept while I speaking
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so many factors to be trouble in IoT
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so many factors to be trouble in IoT
peripheral equipments (☆)
circuit and wiring design
printed circuit board = PCB
soldering (☆)
C, mruby and mruby/c (☆)
communication timing control (☆)
network
☆...I will explain these topics
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peripheral equipments
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peripheral equipments
it is very important to check these
things before writing application code
equipment like sensor or
communication module works as its
spec sheet
whether the equipment is not
broken (sometimes broken by
soldering 😭)
unless you will regret
so...
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peripheral equipments
Raspberry Pi & CRuby are great for pre-
prototyping
use breadboard or make PCB for test
like this photo
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peripheral equipments
ex) CRuby for serial communication test
# notice this is CRuby for RasPi
require 'rubyserial'
require 'timeout'
BAUDRATE = 9600 # match with your instrument
sp = Serial.new '/dev/serial0', BAUDRATE, 8
loop do
puts '[command]'
command = gets
sp.write command.sub("\n", "\r") # replace LF if needed
sleep 0.1
result = ''
begin
Timeout.timeout(10) do
loop do
line = sp.read(128)
break if line == '' && result != ''
result << line
sleep 0.1
puts '=> ' + result
rescue Timeout::Error
puts 'timeout!'
ennnnd
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peripheral equipments
ex) CRuby for serial communication test
$ serial_communication_test.rb
[command]
AT
# command
=> OK
# response
[command]
AT+CIMI
# command
=> 123456789012 # response
[command]
AT+XXX
# command
=> error
# response
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soldering
it may work even if you leave a pin
unsoldered on surface mounting
because the pin touches circuit
then, it will not work one day
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soldering
all the cause of failure, it is impatience
すべての失敗の原因、それは焦り
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mruby and mruby/c
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mruby and mruby/c
mruby
an ecosystem of interpreter, compiler
(mrbc), shell(mirb) and virtual
machine and mrbgems
mruby/c
VM(smaller than mruby), rrt0 and hal
(hardware abstraction layer)
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mruby and mruby/c
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mruby and mruby/c
mruby
v1.0.0 in Jan 2014
mrbgems
RAM < N*100KB
mruby/c
v1.0 in Jan 2017
no package
manager
RAM < 64KB
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coming up features to mruby/c
task priority
at this point, tasks run as simple
round robbin schedule, although we
can use Mutex
instance variable
at this point, you can use constants
and globals
in fact, you can use these features above.
just not announced
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coming up features to mruby/c
compile option of including <math.h>
to reduce memory usage
Array#each and Hash#each
and Hash#to_json will come
note that now you can compile
`#each` with mrbc but it will not run
on mruby/c's VM
in short, mruby/c VM has less
methods than mruby VM
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how does mruby/c work
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how does mruby/c work
~/sample_project
├── main.c
├── mrblib
│
├── job_1.rb
│
└── job_2.rb
└── src
├── job_1.c
└── job_2.c
job_*.c are compliled code from
job_*.rb
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how does mruby/c work
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how does mruby/c work
/* main.c */
#include "src/job_1.c"
#include "src/job_2.c"
// use 30KB RAM for VMs in this case
#define MEMORY_SIZE (1024*30)
static uint8_t memory_pool[MEMORY_SIZE];
int main(void) {
mrbc_init(memory_pool, MEMORY_SIZE);
mrbc_create_task(job_1, 0);
mrbc_create_task(job_2, 0);
mrbc_run(); // 2 tasks run concurrently!
return 0;
// we will not write `main loop` in main.c
}
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how does mruby/c work
we can run easily multiple VMs with
concurrency due to rrt0
you might be disappointed to know
you have to write C
yes, we have to write main.c
don't worry, it's almost boilerplate
code
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how does mruby/c work
~/mrubyc $ tree src -P *.h
src
├── alloc.h
├── c_array.h
...
├── console.h
├── errorcode.h
├── global.h
├── hal_posix
│
└── hal.h
├── hal_psoc5lp
│
└── hal.h
├── load.h
├── mrubyc.h
├── opcode.h
├── rrt0.h
├── static.h
├── symbol.h
├── value.h
├── vm.h
└── vm_config.h
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how does mruby/c work
~/mrubyc $ tree src -P *.h
src
├── alloc.h
├── c_array.h
...
├── console.h
├── errorcode.h
├── global.h
├── hal_posix
│
└── hal.h # hal for posix
├── hal_psoc5lp
│
└── hal.h # hal for PSoC5LP
├── load.h
├── mrubyc.h
├── opcode.h
├── rrt0.h
├── static.h
├── symbol.h
├── value.h
├── vm.h
└── vm_config.h
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how does mruby/c work
~/mrubyc $ tree src -P *.h
src
├── alloc.h
├── c_array.h
...
├── console.h
├── errorcode.h
├── global.h
├── hal_posix
│
└── hal.h
├── hal_psoc5lp
│
└── hal.h
├── load.h
├── mrubyc.h
├── opcode.h
├── rrt0.h
# runtime scheduler
├── static.h
├── symbol.h
├── value.h
├── vm.h
└── vm_config.h
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how does mruby/c work
~/mrubyc $ tree src -P *.h
src
├── alloc.h
├── c_array.h
...
├── console.h
├── errorcode.h
├── global.h
├── hal_posix
│
└── hal.h
├── hal_psoc5lp
│
└── hal.h
├── load.h
├── mrubyc.h
├── opcode.h
├── rrt0.h
├── static.h
├── symbol.h
├── value.h # this gives you hints about variable
├── vm.h
└── vm_config.h
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how does mruby/c work
~/mrubyc $ tree src -P *.h
src
├── alloc.h
├── c_array.h
...
├── console.h
├── errorcode.h
├── global.h
├── hal_posix
│
└── hal.h
├── hal_psoc5lp
│
└── hal.h
├── load.h
├── mrubyc.h
├── opcode.h
├── rrt0.h
├── static.h
├── symbol.h
├── value.h
├── vm.h
└── vm_config.h # edit this if needed
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debugging
we can neither do step execution nor
look into memory to see mruby/c
variables
before writing app code, we should
prepare way of debug
let's go with old-fashioned 'print
debug'. it'll be almost enough
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debugging
/* add this snippet into main.c */
// create serial console with UART for debug print
// http://www.s-itoc.jp/activity/research/mrubyc/mrubyc_tutorial/737
static void c_debugprint(mrb_vm *vm, mrb_value *v, int argc){
int total, used, free, fragment;
mrbc_alloc_statistics(&total, &used, &free, &fragment);
console_printf(
"Memory total:%d, used:%d, free:%d, fragment:%d\n",
total, used, free, fragment);
unsigned char *key = GET_STRING_ARG(1);
unsigned char *value = GET_STRING_ARG(2);
console_printf("%s:%s\n", key, value );
}
int hal_write(int fd, const void *buf, int nbytes){
UART_DEBUG_PutArray(buf, nbytes);
return nbytes;
}
int hal_flush(int fd){
return 0;
}
int main(void) {
mrbc_define_method(0, mrbc_class_object, "debugprint", c_debugprint);
}
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debugging
# mruby
pi = 3.14
debugprint('Pi', pi)
=> # print in serial console like 'PuTTY' connecting USB
Memory total:30000, used:20000, free:10000, fragment:3
Pi:3.14
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actual source code
http://github.com/
hasumikin/rubykaigi2018_demo.cydsn
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actual source code
~/rubykaigi2018_demo.cydsn
├── main.c
├── mrblib
│
├── job_3gmodule.rb # transmit JSON data to cloud
│
├── job_breath.rb
# hit 3gmodule periodically to send data
│
├── job_co2.rb
# measure CO2 concentration
│
├── job_heartbeat.rb # show values on LED
│
└── job_humidity_deficit.rb # measure humidity deficit(HD)
└── src
├── job_3gmodule.c
├── job_breath.c
├── job_co2.c
├── job_heartbeat.c
└── job_humidity_deficit.c
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actual source code
# job_heartbeat.rb
$mutex = Mutex.new # rrt0 has Mutex functionality
while true # this is a `main loop`
r_LED_Driver_ClearDisplayAll # wrapper method of C func
$co2 = measure_co2 # defined in job_co2.rb
$hd = measure_humidity_deficit # job_humidity_deficit.rb
$mutex.lock() # to prevent other jobs from overwriting LED
r_LED_Driver_WriteString7Seg(sprintf('%4d', $co2), 0)
r_LED_Driver_WriteString7Seg(sprintf('%3.0f', $hd * 10), 4)
r_LED_Driver_PutDecimalPoint(1, 5)
r_LED_Driver_WriteString7Seg('g', 7)
$mutex.unlock()
sleep 3
end
how does
r_LED_Driver_WriteString7Seg() work?
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actual source code
/* add into main.c */
#include "src/job_heartbeat.c"
static void c_LED_Driver_WriteString7Seg(
mrb_vm *vm, mrb_value *v, int argc){
char *string = GET_STRING_ARG(1); // see value.h
int position = GET_INT_ARG(2);
// this is defined in IDE's framework
LED_Driver_WriteString7Seg(string, position);
}
int main(void){
...
mrbc_define_method(0, mrbc_class_object,
"r_LED_Driver_WriteString7Seg",
c_LED_Driver_WriteString7Seg);
...
}
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actual source code
# job_breath.rb
$state = 'initializing'
while !$mutex # wait until main loop runs
relinquish()
end
sleep 10 # wait for 3G module starts
$state = 'waiting' if check_3gmodule
while true
if $state != 'sending'
$state = 'ready_to_send'
end
sleep 300 # send data every 5 mins
end
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actual source code
# job_3gmodule.rb(excerpt)
while true
if $state == 'ready_to_send'
$state = 'sending'
i = 0
while true
flag = send_data(json($co2, $humidity_deficit))
if flag
$mutex.lock()
r_LED_Driver_WriteString7Seg('sendgood', 0)
sleep 1
$mutex.unlock()
break
else
$mutex.lock()
r_LED_Driver_WriteString7Seg('sendfail', 0)
sleep 1
r_LED_Driver_WriteString7Seg('retry', 0)
sleep 1
$mutex.unlock()
end
if i > 2
j = 0
$mutex.lock()
while j < 20
j += 1
r_LED_Driver_WriteString7Seg('fatalerr', 0)
sleep 0.2
r_LED_Driver_ClearDisplayAll
sleep 0.05
break
end
$mutex.unlock()
end
i += 1
end
debugprint('memory', 'check')
$state = 'waiting'
ennd
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actual source code
# job_co2.rb does not have loop
def measure_co2
r_UART_CO2_ClearTxBuffer
r_UART_CO2_ClearRxBuffer
ary = [0xff,0x01,0x86,0x00,0x00,0x00,0x00,0x00,0x79]
r_UART_CO2_PutArray(ary, ary.size) # this will be explained
res = []
i = 0
# can't write `for i in 0..3`, equiv. of #each
while i < 4
res[i] = r_UART_CO2_GetByte
i += 1
end
if res[0] == 255 && res[1] == 134
return res[2] * 256 + res[3]
else
return false
ennd
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actual source code
/* add into main.c */
// mruby array should be converted into C array
static void c_UART_CO2_PutArray(
mrb_vm *vm, mrb_value *v, int argc){
mrb_value mrbc_array = GET_ARY_ARG(1);
uint8 array[GET_INT_ARG(2)];
for( int i = 0; i < GET_INT_ARG(2); i++ ) {
mrb_value value = mrbc_array_get(&mrbc_array, i);
array[i] = value.i;
}
UART_CO2_PutArray(array, GET_INT_ARG(2));
}
uint8 tmpStat;
do { // will be explained later
tmpStat = UART_CO2_ReadTxStatus();
} while (~tmpStat & UART_CO2_TX_STS_COMPLETE);
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actual source code
you can pass string instead of mruby/
c array
it was a sample to handle mrb_value
I also wanted argument class(Array)
to correspond with method name
(xxx_PutArray)
use string instead of array if memory
becomes short
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actual source code
/* add into main.c */
// mruby array should be converted into C array
static void c_UART_CO2_PutArray(
mrb_vm *vm, mrb_value *v, int argc){
mrb_value mrbc_array = GET_ARY_ARG(1);
uint8 array[GET_INT_ARG(2)];
for( int i = 0; i < GET_INT_ARG(2); i++ ) {
mrb_value value = mrbc_array_get(&mrbc_array, i);
array[i] = value.i;
}
UART_CO2_PutArray(array, GET_INT_ARG(2));
}
uint8 tmpStat;
do { // communication timing control here
tmpStat = UART_CO2_ReadTxStatus();
} while (~tmpStat & UART_CO2_TX_STS_COMPLETE);
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actual source code
communication of microcontroller
takes time
we will not get notification something
like callback from peripheral
we have to wait until it's ready
we can write another wrapper for
waiting
but we want to reduce memory usage
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development environment
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development environment
IDE `PSoC Creator`
you need to use it for periferal
arrangement and pin assignment
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development environment
IDE `PSoC Creator`
you need to use it for periferal
arrangement and pin assignment
runs only on Windows
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development environment
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development environment
do you hate IDE?
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development environment
do you hate IDE?
#MeeToo
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development environment
do you hate IDE?
#MeeToo
I made a tool for Linux and macOS
github.com/hasumikin/mrubyc-
utils
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development environment
your_project $ mrubyc-utils --help
Usage: mrubyc-utils COMMAND [ARGS]
install
Install mruby/c repo into your local and setup templates.
Please run this command at the top directory
of your project (normally it should have 'main.c').
update
Update mruby/c repo to the newest master branch.
checkout
Checkout specified tag or commit of mruby/c repo.
-t | --tag
[required] You can specify anything that
`git checkout` will accept.
tag
Show all tags of mruby/c repogitory that you installed.
classes
Show all the classes that are defined in
mruby/c's virtual machine.
methods
Show all the methods that are available
in specified class of mruby/c.
-c | --class
[required] You have to specify class name
compile
Compile your mruby source into C byte code.
-w | --watch
[optional] Monitoring loop runs and it will
compile mruby source every time you save.
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development environment
your_project $ mrubyc-utils install
(...install mruby/c and template files)
your_project $ mrubyc-utils compile
(...you can specify --watch option)
your_project $ tree
├── .gitignore
├── .mrubyc/
├── .mrubycconfig
├── main.c
├── mrblib
│
├── job_main_loop.rb
│
├── job_operations.rb
│
└── job_sub_loop.rb
├── mrubyc_src
(...)
│
└── vm_config.h
└── src
├── job_main_loop.c
├── job_operations.c
└── job_sub_loop.c
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development environment
your_project $ mrubyc-utils classes
- Array
- False
- Fixnum
- Float
- Hash
- Mutex
- Nil
- Object
- Proc
- Range
- String
- Symbol
- True
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development environment
your_project $ mrubyc-utils methods --class=array
Array
- +
- <<
- []
- []=
- at
- clear
- count
- delete_at
- dup
- empty?
- first
- index
- last
- length
- pop
- push
- shift
- size
- unshift
< Object
- !
- !=
- <=>
- attr_accessor
- attr_reader
- change_priority
- class
- get_tcb
- instance_methods
- new
- p
- puts
- relinquish
- resume_task
- sleep
- sleep_ms
- sprintf
- suspend_task
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development environment
using mrubyc-utils, you can minimize
uses of IDE to these:
build setting
peripheral arrangement and pin
assignment
build
then you can write app code with vim,
emacs or textbringer
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what you can do for mruby/c
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what you can do for mruby/c
write another hal
so that mruby/c can be suitable for
more microcontrollers
write documentation, test and real
applications
publish that you use mruby/c
posix...
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demo (this was added after Kaigi)
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demo (this was added after Kaigi)
CO2 kept around 700ppm while I was
talking!
ventilating facilities of Sendai
International Center are so goooood!
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about me
HASUMI Hitoshi （羽角 均）
Monstar Lab （モンスター・ラボ）
Matsue office （島根開発拠点）
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conclusion
you should refresh air
換気大事
