Who is Phil Coval

• Software Engineer from Rennes, France
• OpenSource Contributor, Mozilla Rep (IoT)
• Involved in OS projects supported by industry:
  • Tizen (Intel), IoTivity (Samsung), OSTC-EU
• Contact: https://purl.org/rzr
  • Currently available for cooperation
  • Link me from Fediverse or @RzrFreeFr
    • Presentations, Videos, Social
• Interests: FLOSS Community, IoT, 3D/XR…

Demo Walkthrough

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Context

• This demo illustrates:
  • Web Of Twins experiments
  • Distributed online env (Mozilla Hubs)
• From "Quick and dirty" demo
  • to top quality upstream code
• Hint: Isolate changes and features
  • Smallest Atomic commits

NuttX RTOS

• Committed to comply standards
  • POSIX, ANSI C
  • File based IO (/dev), BSD sockets (uIP)
• Released by Gregory Nutt in 2007
  • Incubated by Apache Foundation
    • https://nuttx.apache.org/
• Base of derived projects:
  • TizenRT, PX4, Sony Spresense

Getting started

• Operating System is FLOSS (Apache-2.0)

  git clone https://github.com/apache/incubator-nuttx \
    nuttx -b nuttx-10.1.0
  git clone https://github.com/apache/incubator-nuttx-apps \
    apps -b nuttx-10.1.0
  

• Documentation:

  less Documentation/index.rst
  

  • https://nuttx.apache.org/docs/latest/
• NuttX Channel (Thx Alan)
  • https://youtube.com/NuttXChannel

Board support

• 200+ supported boards (and configurations)

  ./tools/configure.sh -L
  

• Several architectures from 8 to 64 bits
  • ./boards/{arm,avr,mips,risc-v,x86…}
  • … and sim for simulator

NXP Freedom Board

• Frdm-k64F

  • CPU: Arm® Cortex®-M4
  • RAM=256K, Flash=1024K

  cat arm/kinetis/freedom-k64f/README.txt
  ./tools/configure.sh freedom-k64f:nsh
  make && stat -c '%s' nuttx.bin # 82296 bytes
  cp nuttx.bin /media/$USER/BOOTLOADER/
  

• https://github.com/apache/incubator-nuttx/issues/1988

Board port

• Dir "boards/arm/kinetis/freedom-k64f"
  • README.txt
  • configs/{nsh,netnsh,demo…}/defconfig
  • src/k64_bringup.c : Boot
  • src/*.c for IO / peripherals

I2C Support

• freedom-k64f/src/k64_i2c.c
  • i2c_register(g_i2c0_dev, 0)
• freedom-k64f/src/k64_bringup.c
  • k64_i2cdev_initialize
• Configure build using:
  • CONFIG_SYSTEM_I2CTOOL, KINETIS_I2C0
• https://github.com/apache/incubator-nuttx/pull/1982/

Using I2C Bus

• i2c tool is very familiar to Linux's one

  nsh> i2c bus
  Bus 0: YES
  
  nsh> i2c dev 1 0x7F
  10: -- -- -- -- -- -- -- -- -- -- -- -- -- 1d -- --
  
  nsh> i2c get -a 1d -r 0d
  #| READ Bus: 0 Addr: 1d Subaddr: 0d Value: c7
  

• 0x1d is F64F's onboard sensor

Sensor Module

• FRDM K64F's onboard sensor (IC)
• FXOS8700cq module is composed of
  • accelerometer + magnetometer (3-axis)
• Datasheet explains I2C protocol and structures
  • https://www.nxp.com/docs/en/data-sheet/FXOS8700CQ.pdf

Implement driver

• drivers/sensors/fxos8700cq.c
  • fxos8700cq_register
    • devpath = "/dev/accel0"
    • register_driver(devpath, &g_fxos8700cqfops, 0666, priv);
• Reconfigure to enable SENSORS_FXOS8700CQ
• https://github.com/apache/incubator-nuttx/issues/1988

Register driver

• freedom-k64f: Register on board sensor driver
• freedom-k64f/src/k64_i2c.c
• k64_i2cdev_initialize
• fxos8700cq_register("/dev/accel0", g_i2c0_dev);
• https://github.com/apache/incubator-nuttx/pull/1999

Sensor Application

• Configure with EXAMPLES_FXOS8700CQ

• Read data from "/dev/accel0" (in loop)

  nsh> fxos8700cq
  { accel: [2174, 555, -752], magn: [0, 0, 0] }
  { accel: [-300, 547, 1951], magn: [55, -188, 276] }
  

• https://github.com/apache/incubator-nuttx-apps/pull/428

Enable networking

• Configure
  • NET_UDP, NET_TCP, NETDB_DNSCLIENT
  • ETH0_PHY_KSZ8081. ETH0_PHY_KSZ8081
  • SYSTEM_DHCPC_RENEW

• Usage:

  nsh> ifconfig
  eth0    Link encap:Ethernet HWaddr (...) at UP
  nsh> renew eth0 && ifconfig
  eth0    Link encap (...) inet addr:192.168.1.42
  

Add network app:

• Implemented netcat to stream data
  • apps/netutils/netcat/README.md

• As server or client

  netcat 192.168.1.55 31337 /proc/version
  

• Select application NETUTILS_NETCAT
• https://github.com/apache/incubator-nuttx/pull/2333
• https://github.com/apache/incubator-nuttx-apps/pull/482

Pipe stream

mkfifo /dev/fifo
fxos8700cq > /dev/fifo &
fxos8700cq [7:100]
netcat 192.168.1.55 31337  /dev/fifo

Summary

• NuttX RTOS is
• Supporting standards
  • Close to Linux
• base to adapt to new hardware
  • Boards bringup
  • Peripheral drivers
• Supporting applications
  • OS can chain them

Resources and more:

• https://purl.org/rzr
• https://purl.org/rzr/weboftwins
• https://purl.org/rzr/presentations

Extra Challenge

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Extra Demo

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Video Playback

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Upcoming

• https://purl.org/rzr/presentations

More

• https://purl.org/rzr
• https://purl.org/rzr/presentations
• https://purl.org/rzr/demo
• https://purl.org/rzr/weboftwins
• https://purl.org/rzr/social
• https://purl.org/rzr/video

Related

Playlist

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