====== Linux on Sharp Brain ======

{{::brainux_linux_sharp-brain.png?800|}}


I have much interest in this kind of devices. The [[Sharp Brain]] is electronic dictionary for Japanese people to learn English. But it's kind of computer. Some time ago I bought six of them. Since I do not understand Japanese at all, and everything about these devices is described only in Japanese, here I will describe the essentials of how to run and use the GNU/Linux system. I will also try to find out what can be done with the device and software.

**Presentation of running Linux on Sharp brain devices can be found [[http://mirror.vintage2000.org/brain/wakate2022_english.pdf|here]] (english translation) and original (Japanese) [[http://mirror.vintage2000.org/brain/wakate2022.pdf|here]].**
 
===== Build =====

You will need Linux Computer or Virtual Machine with [[https://www.debian.org/releases/buster/debian-installer/|Debian 10 (Buster)]] or [[https://releases.ubuntu.com/focal/|Ubuntu 20.04 LTS]]. **Keep note** i will use build configuration for [[Sharp Brain]] **PW-SA2** (**3rd** generation model) in this tutorial.

Install the required packages to make your system as build host:
  sudo apt install build-essential bison flex libncurses5-dev gcc-arm-linux-gnueabi debootstrap qemu-user-static \
   gcc-arm-linux-gnueabihf libssl-dev bc lzop qemu-user-static kpartx
Clone the repository to your machine:   
  git clone --recursive https://github.com/brain-hackers/buildbrain.git
Prepare the build configuration:
  cd buildbrain
  make udefconfig-sh2 # you can use udefconfig-sh3 if your model is SH3 or so
Now build the boot loader:
  make ubuild 
  make nkbin-maker
  make nk.bin
Build Linux distribution:
  make ldefconfig # generates Linux .config
  make lbuild # builds Linux kernel
  make aptcache # this is the last command in current terminal it stays in the background
As you missed my last # comment, you have to leave last command running in the current terminal and open new terminal or tab.  

You can add your own debian packages to the default install by editing file **os-brainux/setup_brainux.sh** at **line 80** you can put something like:
  apt install -y dialog sudo \
                   libjpeg-dev libfreetype6 libfreetype6-dev zlib1g-dev \
                   xserver-xorg xserver-xorg-video-fbdev xserver-xorg-dev xserver-xorg-input-evdev xinput-calibrator xorg-dev x11-apps xi>
                   openbox obconf jwm \
                   weston xwayland \
                   bash tmux vim htop \
                   midori pcmanfm lxterminal xterm gnome-terminal fbterm uim-fep uim-anthy fonts-noto-cjk \
                   dbus udev alsa-utils usbutils iw fake-hwclock systemd-timesyncd\
                   build-essential flex bison pkg-config autotools-dev libtool autoconf automake device-tree-compiler mc \
                   python3 python3-dev python3-setuptools python3-wheel python3-pip python3-smbus \
                   resolvconf net-tools ssh openssh-server openssh-client avahi-daemon wget git \
                   network-manager zip neofetch sl python3-numpy ipython3 netsurf-gtk fcitx-anthy \
                   neofetch net-tools # your packages

When continue with building the distribution:
 make brainux

Now after you have finished making the Linux distribution move to the next section..

===== Setup MicroSD Card =====  

**NOTE!** This procedure will erase the contents of the SD card. Always make a backup before doing this.

**NOTE2!** If your Linux distribution automatically mounts the MicroSD card, then make sure to unmount it before proceeding..

  umount /dev/sdb1 # where your sd is located

Install gparted in your system:
  sudo apt install gparted
Launch gparted:
  sudo gparted

**Change disk** to your MicroSD card  

{{::sharp-brain_linux_pt1.png?600|}}

**Delete all partitions on the MicroSD card**..
  
Create a **FAT32** partition of about **100MB**. For my setup i will use **2GB FAT32** partition, because i have 32GB MicroSD card and it's a lot of space.

{{::sharp-brain_linux_pt2.png?600|}}

The rest of the space we will use for the **EXT4** file system (**For Linux**).

{{::sharp-brain_linux_pt3.png?600|}}

Now the **MicroSD** card file systems layout should look like this:

{{::sharp-brain_linux_pt4.png?600|}}

Click **Apply All Operations**.
  
  
===== Install =====

Mount file systems from newly created **MicroSD** card:
  mkdir /mnt/sd{1,2}
  mount /dev/sdb1 /mnt/sd1 # FAT32
  mount /dev/sdb2 /mnt/sd2 # EXT4
Copy **Linux distribution** to **EXT4** partition:  
  sudo cp -ar ./brainux/* /mnt/sd2/
Copy **Linux Kernel** files to **FAT32** partition:  
  cp linux-brain/arch/arm/boot/zImage /mnt/sd1/
  cp linux-brain/arch/arm/boot/dts/imx28-pwsh2.dtb /mnt/sd1
  
The **imx28-pwsh2.dtb** depends on the model you have. You can use (//pwsh1,pwsh2,pwsh3,pwsh4,pwsh5,pwsh6,pwsh7//). 

Of course you can copy them all:
  cp linux-brain/arch/arm/boot/dts/imx28-pwsh{1,2,3,4,5,6,7}.dtb /mnt/sd1/

Now, there is no longer need to load Linux from [[windows:Windows CE]] environment, it can be loaded directly when the device is booting by **nk.bin**. 

Copy bootloader files:
  cp u-boot-brain/u-boot.sb /mnt/sd1/
  cp u-boot-brain/u-boot.bin /mnt/sd1/

So please Copy **nk.bin** to **/mnt/sd1/(`ed[a-z]{2}[0-9]exe.bin`)** filename for the specific model in this table.. Mine is SX2:
  cp nk.bin /mnt/sd1/EDSA2EXE.BIN

^ Model ^ File name ^
| PW-G5300 | EDNA3EXE.BIN |
| PW-Sx1 | EDSA1EXE.BIN |
| PW-Sx2 | EDSA2EXE.BIN |
| PW-Sx3 | EDSA3EXE.BIN |
| PW-Sx4 | EDSH4EXE.BIN |
| PW-Sx5 | EDSA5EXE.BIN |
| PW-Sx6 | EDSA6EXE.BIN |
| PW-Sx7 | EDSA7EXE.BIN |

**Umount** the **MicroSD** card partitions:
  umount /dev/sdb{1,2}

**Now you are ready to run**

===== Run =====

Insert **MicroSD** card to the [[Sharp Brain]] and **reset** device. Then prompted for the username/password use these:
  user:brain
  
==== Keyboard Layout ====

{{::sharp-brain-pw-sa2_keyboard-translated.jpeg?1200|}}

{{::keymap.png?600|}}  


==== Swap ====

  dd if=/dev/zero of=/swapfile bs=1M count=256 # 256MB Swap file
  mkswap /swapfile
  swapon /swapfile
  echo "/swapfile swap swap defaults 0 0" >> /etc/fstab

==== MicroUSB OTG Cables ====  

Brainux defaults to the USB controller acting as a host. With an OTG cable you can connect any device you like. Brain itself doesn't have the ability to supply his VBUS (5V), so you'll need to use an OTG cable that can be powered separately.
 
  * [[https://amz.run/4Kue|RouteR RUH-OTGU4]]
  * [[https://www.sengoku.co.jp/mod/sgk_cart/detail.php?code=EEHD-5EHA|AINEX USB-120R]]
  * [[https://amz.run/4LXg|CY 90 Degree Left Right Angled Micro USB 2.0 OTG Host Adapter]]

==== USB Ethernet ==== 

Just by connecting a PC that can connect to the Internet and Brain, you can go out to the Internet from Brain and SSH in both directions between the PC and Brain. No need to worry about running out of battery. By default, Brain's USB controller acts as a host, so it cannot act as a device. There are way to switch the operating mode of the controller: using a tool called **brain-config**.

  sudo brain-config
  sudo reboot
  
=== Internet Sharing script for Linux machine ===

  * **wlx74da38f5c024** -> wifi interface or interface where internet is provided
  * **usb0** -> is the usb cable connected to the sharp brain

  #!/bin/sh
  iptables --table nat -A POSTROUTING --out-interface wlx74da38f5c024 -j MASQUERADE
  iptables -A FORWARD --in-interface wlx74da38f5c024 -j ACCEPT
  echo 1 > /proc/sys/net/ipv4/ip_forward
  ifconfig usb0 down
  ifconfig usb0 192.168.7.1
  ifconfig usb0 up
  dnsmasq -d -i usb0  \
    --filterwin2k -p0 --dhcp-range=192.168.7.2,192.168.7.20 \
    -O 3,192.168.7.1 -O 6,1.1.1.1 --log-dhcp  --server=8.8.8.8 --server=8.8.4.4 \
    --dhcp-lease-max=253 --dhcp-authoritative  
Save it to **brain.sh** and provide executable permissions:
  chmod +x brain.sh
When ready to share internet to the **Sharp brain**, just execute it:
  ./brain.sh
  
=== Internet Sharing on Windows/Mac machine ===  

Read auto translated tutorial [[https://wiki-brainux-org.translate.goog/tips/usb-ethernet-gadget/?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp#pc-%E5%81%B4%E3%81%AE%E5%AF%BE%E5%BF%9C%E4%BD%9C%E6%A5%AD|here]]

==== Dosbox under Brainux ====  

You should add **dosbox** package when building brainux from scratch.. See the **build section** of this tutorial.

  export SDL_NOMOUSE=1
  dosbox

Some buttons are not binded correctly, i'm working on the solution right now.

----

Same big parts of this tutorial where translated from the [[https://brain.fandom.com/ja/wiki/Brain_Wiki|original Japanese wiki]] about the **Sharp Brain**.

Greetings are flying out to [[https://github.com/brain-hackers|brain-hackers]]

{{keywords>brainux,sharp brain,sharp,brain,linux,brainux build,wince,nk.bin,eboot}}