Text
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pico
ruby
THE RISE OF MICROCONTROLLER
EPISODE Ⅳ
@hasumikin
RubyConf Taiwan 2023
Dec. 15, 2023
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Find PicoRuby's history on the internet
EPISODE Ⅱ
ATTACK OF THE RAKE
EPISODE Ⅲ
REVENGE OF THE STDIN
Extra edition in Euruko 2023
"A Beginner's Complete Guide"
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self.inspect
Hitoshi HASUMI
hasumikin (GitHub ,ex-Twitter, Bluesky and Mastodon)
Creator of PicoRuby and PRK Firmware
Committer of CRuby's IRB and Reline
First prize of Fukuoka Ruby Award
(2020 and 2022 )
A final nominee of Ruby Prize 2021
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I have a favor to ask
If possible, please turn off your Bluetooth
To avoid channel congestion during my talk
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Let's begin 1/5
Connect Pi Pico and PC while
pressing the BOOTSEL button
You'll find "RPI-RP2" drive
in file manager
https://www.raspberrypi.org/documentation/rp2040/getting-started
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Let's begin 2/5
Download the latest
`R2P2-*.uf2`
from GitHub
https://github.com/picoruby/R2P2/releases
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Let's begin 3/5
Drag & drop `R2P2-*.uf2` into RPI-RP2 drive
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Let's begin 4/5
Open a proper
serial port on
terminal emulator
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Let's begin 5/5
R2P2 is a Unix-like shell
running on Pi Pico
You can use some
commands like `cd`,
`ls`, `mkdir`, and `irb`
Every computing process
is happening on Pi Pico
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By the way, R2P2 stands for
Ruby on
Raspberry
Pi
Pico
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Today's setup
Raspberry Pi Pico W * 2
AQM0802 charactor
display module
ADT7310 thermo
sensor module
FTDI USB-TTL serial
coverter cable
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Raspberry Pi "Pico" and "Pico W"
Pico Pico W
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GPIO
irb>
#
irb>
irb>
irb>
irb*
irb*
irb*
irb*
irb*
gpio = CYW43::GPIO.new(CYW43::GPIO::LED_PIN)
gpio = GPIO.new(25, GPIO::OUT) # If Pico w/o W
gpio.write 1 #=> LED turns on
gpio.write 0 #=> LED turns off
3.times do
gpio.write 1
sleep 1
gpio.write 0
sleep 1
end
#=> LED blinks three times
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LED wraps GPIO
# /lib/led.rb in R2P2 drive
require 'gpio'
require 'cyw43'
CYW43.init
class LED
def initialize
@gpio = CYW43::GPIO.new(CYW43::GPIO::LED_PIN)
#
= GPIO.new(25, GPIO::OUT) # If Pico w/o W
end
def on
@gpio.write 1
end
def off
@gpio.write 0
end
def invert
@gpio.read == 1 ? off : on
end
end
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LED wraps GPIO
irb>
irb>
irb>
irb*
irb*
irb*
require 'led'
led = LED.new
3.times do
led.invert
sleep 1
end
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Peripherals for serial communication
I2C: To communicate between integrated circuits
with support for multiple devices connected to the
same bus
SPI: To facilitate high-speed communication between
microcontrollers and peripheral devices
UART: To establish asynchronous serial
communication between devices
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I2C
irb>
irb>
irb>
irb>
irb>
irb>
irb>
require 'i2c'
i2c = I2C.new(unit: :RP2040_I2C1, sda_pin: 26, scl_pin: 27)
[0x38, 0x39, 0x14, 0x70, 0x56, 0x6c].each { |i| i2c.write(0x3e, 0, i); sleep_ms 1 }
[0x38, 0x0c, 0x01].each { |i| i2c.write(0x3e, 0, i); sleep_ms 1 }
"Hello,".bytes.each { |c| i2c.write(0x3e, 0x40, c); sleep_ms 1 }
i2c.write(0x3e, 0, 0x80|0x40)
"Taiwan!".bytes.each { |c| i2c.write(0x3e, 0x40, c); sleep_ms 1 }
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LCD wraps I2C
# /lib/lcd.rb in R2P2 drive
require 'i2c'
class LCD
ADDRESS = 0x3e # 0x7c == (0x3e << 1) + 0 (R/W)
def initialize(i2c:)
@i2c = i2c
reset
end
def reset
[0x38, 0x39, 0x14, 0x70, 0x56, 0x6c].each { |i| @i2c.write(ADDRESS, 0, i) }
sleep_ms 200
[0x38, 0x0c, 0x01].each { |i| @i2c.write(ADDRESS, 0, i) }
end
def putc(c)
@i2c.write(ADDRESS, 0x40, c)
sleep_ms 1
end
def print(line)
line.bytes.each { |c| putc c }
end
# ...
# See https://github.com/picoruby/picoruby/tree/master/mrbgems/picoruby-ble/example/broadcaster-observer
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LCD wraps I2C
irb>
irb>
irb>
irb>
irb>
require 'lcd'
lcd = LCD.new(i2c: I2C.new(unit: :RP2040_I2C1, sda_pin: 26, scl_pin: 27))
lcd.print "Hello,"
lcd.break_line
lcd.print "Taiwan!"
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SPI
irb> require 'spi'
irb> spi = SPI.new(unit: :RP2040_SPI0, cipo_pin: 16,
cs_pin: 17, sck_pin: 18, copi_pin: 19)
irb> spi.select
irb> spi.write(255,255,255,255) # Reset
irb> spi.write(0x54)
# Start continuous mode
irb> data = spi.read(2).bytes
irb> temp = data[0] << 8 | data[1]
irb> temp / 128.0
# Convert to Celsius
=> 19.5621
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THERMO wraps SPI
# /lib/thermo.rb in R2P2 drive
require 'spi'
class THERMO
def initialize(unit:, sck_pin:, cipo_pin:, copi_pin:, cs_pin:)
@spi = SPI.new(unit: unit, frequency: 500_000, mode: 0, cs_pin: cs_pin,
sck_pin: sck_pin, cipo_pin: cipo_pin, copi_pin: copi_pin
)
@spi.select
@spi.write 0xFF, 0xFF, 0xFF, 0xFF # Reset
@spi.write 0x54 # Start continuous mode
sleep_ms 240
end
def read
data = @spi.read(2).bytes
temp = (data[0] << 8 | data[1]) >> 3
# If it minus?
temp -= 0x2000 if 0 < temp & 0b1_0000_0000_0000
temp / 16.0 # Convert to Celsius
end
end
# See https://github.com/picoruby/picoruby/tree/master/mrbgems/picoruby-ble/example/broadcaster-observer
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THERMO wraps SPI
irb> require 'thermo'
irb> thermo = THERMO.new(unit: :RP2040_SPI0,
cipo_pin: 16, cs_pin: 17, sck_pin: 18, copi_pin: 19)
irb> thermo.read
=> 19.5621
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LCD and THERMO
irb>
irb>
irb>
irb>
require 'lcd'
lcd = LCD.new(i2c: I2C.new(unit: :RP2040_I2C1, sda_pin: 26, scl_pin: 27))
require 'thermo'
thermo = THERMO.new(unit: :RP2040_SPI0,
cipo_pin: 16, cs_pin: 17, sck_pin: 18, copi_pin: 19)
irb> lcd.print sprintf("%5.2f \xdfC", thermo.read)
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UART
irb> require 'uart'
irb> uart = UART.new(unit:
irb> uart.puts "Hello from
=> nil
irb> while true
irb*
if c = uart.read
irb*
uart.write c
#
irb*
print c
irb*
end
irb* end
Hello to Pico!
#
:RP2040_UART0, txd_pin: 16, rxd_pin: 17, baudrate: 115200)
Pico!"
Echo back
<= "Hello to Pico!" in UART device
You don't need to wrap UART. Use as it is
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BLE Broadcaster
Pin assign
3V3 to {LCD,THERMO}:VCC
GND to {LCD,THERMO}:GND
GPIO16 to THERMO:SDO
GPIO17 to THERMO:CS
GPIO18 to THERMO:SCL
GPIO19 to THERMO:SDI
GPIO26 to LCD:SDA
GPIO27 to LCD:SCL
THERMO
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BLE Observer
Pin assign
3V3 to USB-TTL:VCC
GND to USB-TTL:GND
GPIO16 to USB-TTL:RX
GPIO17 to USB-TTL:TX
USB-TTL
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Gems in Broadcaster and Observer
# in Broadcaster
$> ls /lib
lcd.rb
thermo.rb
# in Observer
$> ls /lib
led.rb
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BLE Broadcaster
# /home/app.rb in R2P2 drive
class DemoBroadcaster < BLE::Broadcaster
def initialize
super(nil)
led = CYW43::GPIO.new(CYW43::GPIO::LED_PIN)
@lcd = LCD.new(i2c: I2C.new(unit: :RP2040_I2C1, sda_pin: 26, scl_pin: 27))
@thermo = THERMO.new(unit: :RP2040_SPI0, cipo_pin: 16, cs_pin: 17, sck_pin: 18, copi_pin: 19)
@counter = 0
end
def adv_data(send_data)
BLE::AdvertisingData.build do |adv|
adv.add(0x01, 0xFF)
adv.add(0x09, "PicoRuby")
adv.add(0xFF, send_data)
end
end
def heartbeat_callback
Machine.using_delay do
temperature = @thermo.read
@lcd.clear
@lcd.print sprintf("%5.2f \xdfC", temperature)
@lcd.break_line
@lcd.print "+" * (@counter % 9)
advertise(adv_data (temperature * 100).to_i.to_s)
end
@counter += 1
Watchdog.update
end
def packet_callback(event_packet)
case event_packet[0]&.ord # event type
when 0x60 # BTSTACK_EVENT_STATE
return unless event_packet[2]&.ord == BLE::HCI_STATE_WORKING
@state = :HCI_STATE_WORKING
Watchdog.enable(2000)
end
end
end
DemoBroadcaster.new.start
# See https://github.com/picoruby/picoruby/tree/master/mrbgems/picoruby-ble/example/broadcaster-observer
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BLE Observer
# /home/app.rb in R2P2 drive
class DemoObserver < BLE::Observer
def initialize
super
@led = LED.new
@uart = UART.new(unit: :RP2040_UART0, txd_pin: 16, rxd_pin: 17, baudrate: 115200)
@uart.puts 'Start BLE Observer Demo'
@last_time_found = Time.now.to_i
Watchdog.enable(4000)
end
def advertising_report_callback(adv_report)
if adv_report&.reports[:complete_local_name] == 'PicoRuby'
now = Time.now.to_i
if 2 < now - @last_time_found
@uart.puts sprintf("%5.2f degC", adv_report.reports[:manufacturer_specific_data].to_f / 100)
@last_time_found = now
end
end
end
def heartbeat_callback
Watchdog.update
@led.invert
end
end
DemoObserver.new.scan(stop_state: :no_stop)
# See https://github.com/picoruby/picoruby/tree/master/mrbgems/picoruby-ble/example/broadcaster-observer
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Real world application
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Wrap up
PicoRuby is a Ruby implementaiton targeting on one-
chip microcontroller
Built-in peripheral gems for general IOs:
GPIO, I2C, SPI, UART, ADC, and PWM are ready
You can incrementally write your device drivers and
applications with PicoIRB
BLE gem is also almost ready for real applications
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stargaze at
github.com/picoruby/picoruby
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may the
source
be with you
