The Perfect Combination: Batocera Linux and a CRT Monitor for the Ultimate Retro Gaming Experience

April 26, 2023

Sony Multiscan CPD E320

The Sony Multiscan CPD E320 is a high-quality CRT (Cathode Ray Tube) monitor that was designed and produced by Sony Corporation. This 21-inch monitor boasts impressive image clarity and color accuracy, making it an ideal choice for professionals in the fields of graphic design, video editing, and other visual-intensive applications. With a maximum resolution of 1600 horizontal dots x 1200 vertical lines, the Sony Multiscan CPD E320 provides users with a large viewing area and sharp, crisp images. Additionally, it features a range of advanced features such as horizontal and vertical moiré reduction, aperture grille technology, and a variety of video inputs. Despite its age, the Sony Multiscan CPD E320 remains a popular choice among those seeking a high-quality CRT monitor for Batocera Linux. Batocera is an operating system for retro gaming that includes pre-configured emulators and other software components, with EmulationStation as the primary graphical frontend for browsing and launching games.

TLDR

As captured on an iPhone 4S, this photograph showcases the Atari 2600 Pac-Man game running on Batocera Linux, displayed on a Sony Multiscan E230 monitor via a native VGA output (no HDMI/DVI adapters). Despite some potential convergence issues, the overall quality of the image is excellent. I love Atari 2600 Pac-Man, it’s just so pokey!

The project “Build-CRT-15KHz-Batocera-V35” is intended for people who want to build a customized gaming system that can output video to a CRT monitor or TV with a 15-31 kHz horizontal refresh rate. This project is especially relevant for those who want to play classic arcade games that were designed to be played on CRT monitors, as these games often rely on the 15-31 kHz refresh rate. Furthermore, this project may appeal to individuals with an interest in constructing and modifying electronic devices, as it entails modifying the software configuration and potentially acquiring an older PC, such as the cost-effective and proficient Dell Optiplex 3020 (Series 4 Optiplex) minitower desktop. This PC model allows for flexibility in its hardware configuration, with the option to upgrade components such as the central processing unit (CPU), graphics card, memory (RAM), power supply unit (PSU), and install multiple hard drives.

The aforementioned github page, provides a bash script that automates the process of configuring Batocera Linux for CRT use. It will prompt the user with a series of questions to gather information about the user’s setup and preferences, and then use that information to modify the necessary configuration files.

The script is designed to be user-friendly and easy to follow, even for those who may not be familiar with Linux configuration. It includes comments and explanations for each step of the process, so users can understand what is happening and why.

Once the script is run, it will modify the necessary configuration files to enable CRT support and configure the display settings accordingly. The user will then be able to connect their CRT monitor and enjoy retro gaming on Batocera Linux with optimal display settings.

HORIZONTAL TIMING SPECIFICATIONS

VERTICAL TIMING SPECIFICATIONS

SYNC TIMING SPECIFICATIONS

Configuring Horizontal and Vertical Sync Timing Specifications for Batocera Linux Video Output

A monitor’s horizontal and vertical sync timing specifications are relevant to Batocera Linux (as well as any other operating system or software that outputs video to a display) because they determine the timing of the video signal that is sent from the graphics hardware to the monitor.

When the graphics hardware generates a video signal, it needs to synchronize the timing of the horizontal and vertical sync signals with the timing of the pixels that make up the video image. If the timing is off, the image may appear distorted, flicker, or not display at all. The monitor’s horizontal and vertical sync timing specifications determine the timing requirements for the sync signals that are needed to properly display the image on the monitor. Batocera Linux (and other operating systems or software that output video) needs to be configured to output video signals that match the timing requirements of the monitor in order to properly display the image. If the video signal output by the operating system or software does not match the timing requirements of the monitor, the image may not display correctly.

Therefore, it is important to ensure that the monitor’s horizontal and vertical sync timing specifications are properly configured in Batocera Linux (or any other operating system or software that outputs video) in order to ensure that the image is displayed correctly on the monitor.

The file that manages the horizontal and vertical sync timing specifications in Batocera Linux is the config.txt file located in the /boot partition of the SD card or USB drive used to boot the system. This file contains various configuration options for the Raspberry Pi hardware, including settings related to the video output.

To configure the horizontal and vertical sync timing specifications in Batocera Linux, you can add or modify the appropriate settings in the config.txt file. Specifically, the hdmi_timings option can be used to set custom horizontal and vertical sync timings for the video output.

However, please note that modifying the config.txt file can be a complex process and may require some technical knowledge. It is important to carefully read the documentation and follow the instructions provided to avoid causing damage to the hardware or rendering the system unusable.

The file that manages the horizontal and vertical sync timing specifications in Batocera Linux on a PC with VGA output is typically the xorg.conf file. This file contains various configuration options for the X Window System, including settings related to the video output.

To configure the horizontal and vertical sync timing specifications in Batocera Linux on a PC with VGA output, you can add or modify the appropriate settings in the xorg.conf file. Specifically, you would need to define a ModeLine with the appropriate timing parameters, such as the sync polarity, horizontal and vertical resolution, and timing parameters.

However, please note that modifying the xorg.conf file can be a complex process and may require some technical knowledge. It is important to carefully read the documentation and follow the instructions provided to avoid causing damage to the hardware or rendering the system unusable.

The xorg.conf file. How to Configure Sony Multiscan CPD E230 Monitor (or equivalent) with VGA Output on Batocera Linux

Here is a sample xorg.conf file for the Sony Multiscan CPD E230 monitor with VGA output on Batocera Linux. Let’s take a look at what it does (aka best attempt).

Section "Monitor"
    Identifier  "Sony Multiscan CPD E230"
    HorizSync   30-96
    VertRefresh 48-160
    ModeLine    "640x480@60" 25.175 640 656 752 800 480 490 492 525
    ModeLine    "800x600@60" 40.000 800 840 968 1056 600 601 605 628
    ModeLine    "1024x768@60" 65.000 1024 1048 1184 1344 768 771 777 806
EndSection
 
Section "Device"
    Identifier  "Standard VGA"
    Driver      "vga"
EndSection
 
Section "Screen"
    Identifier  "Default Screen"
    Device      "Standard VGA"
    Monitor     "Sony Multiscan CPD E230"
    DefaultDepth    24
    SubSection "Display"
        Depth       24
        Modes       "640x480@60" "800x600@60" "1024x768@60"
    EndSubSection
EndSection

In this sample configuration file, we have defined the Sony Multiscan CPD E230 monitor with a horizontal sync range of 30-96 kHz and a vertical refresh rate range of 48-160 Hz. We have also defined three ModeLine configurations for resolutions of 640x480, 800x600, and 1024x768, each with their respective timing parameters. The timing parameters in the ModeLine configurations are in MHz (megahertz) and pixels. The first value after the resolution specifies the pixel clock, which is the rate at which pixels are transmitted by the video card to the monitor. The next eight values are the horizontal timing parameters, which specify the start and end positions of the horizontal blanking interval, the horizontal sync pulse, and the active video area. The last four values are the vertical timing parameters, which specify the start and end positions of the vertical blanking interval, the vertical sync pulse, and the active video area. Finally, we have defined the device and screen sections, with the default screen set to use the Sony Multiscan CPD E230 monitor and the three defined resolutions.

The sample configuration file can be added in Batocera Linux by following these steps:

1. Boot up your Batocera Linux PC and connect it to the monitor.
2. Navigate to the main menu and select “Configuration.”
3. From the Configuration menu, select “Advanced settings.”
4. Scroll down to the “Video output configuration” section and select “Custom mode.”
5. Enter the information from the sample configuration file into the appropriate fields.
6. Save the changes and reboot your system.

Alternatively, you can also add the configuration file by accessing the Batocera Linux system files via SSH or a terminal and manually editing the configuration file located at /userdata/system/batocera.conf. Any changes made to this file will only affect the user’s specific configuration and will not be system-wide. However, it is also possible to modify the global configuration file located at /boot/batocera/batocera.conf, which will affect the system-wide configuration for all users. However, it is generally recommended to make configuration changes in the /userdata/system/batocera.conf file to avoid affecting other users on the system.

After executing the script provided by the GitHub link at the beginning of the article, the /etc/X11/xinit configuration on my system has been updated as follows; We will breakdown what all of it means after this segment of code.

#!/bin/sh

# hide mouse cursor
unclutter --noevents -b

# disable dpms to prevent screen from blanking
xset -dpms
xset s off

# allow coredumps for ES
ulimit -H -c unlimited
ulimit -S -c unlimited emulationstation

# dbus launch is required for the gio/gvfs/trash:///...
eval `dbus-launch --sh-syntax --exit-with-session`

### nvidia ###
nvidia_prime="$(/usr/bin/batocera-settings-get -f /boot/batocera-boot.conf nvidia-prime)"
if test "${nvidia_prime}" = "true"
then
  export __NV_PRIME_RENDER_OFFLOAD=1
  export __VK_LAYER_NV_optimus=NVIDIA_only
  export __GLX_VENDOR_LIBRARY_NAME=nvidia
fi

### radeon ###
# variable for AMD Dynamic Switchable Graphics to take amd-radeon gpu over intel cards when such hybrid cards are available
radeon_prime="$(/usr/bin/batocera-settings-get -f /boot/batocera-boot.conf radeon-prime)"
if test "${radeon_prime}" = "true"
then
    export DRI_PRIME=1
fi

########################
#####-CRT CONFIG-#######
########################
##-Default Resolution-##
########################
xrandr -display :0.0 --newmode "640x480i" 13.10 640 664 728 832 480 484 490 525 interlace -hsync -vsync
xrandr -display :0.0 --addmode VGA-1 "640x480i"
xrandr -display :0.0 --output VGA-1 --mode "640x480i"
########################
########################

openbox --config-file /etc/openbox/rc.xml --startup "emulationstation-standalone"

It looks like the existing configuration is similar to the xorg.conf suggested earlier, which is to use xrandr to add a new mode for the desired resolution and refresh rate, and then set that mode as the output for the display. The only difference is that the existing configuration above is using “640x480i” as the new mode name, whereas the xorg.conf at the top suggests using “320x240_60.00” for a 320x240 resolution with a 60Hz refresh rate.

Interlaced video modes like “640x480i” split the image into two fields, with one field containing even-numbered lines and the other field containing odd-numbered lines. Each field is displayed one after the other, with the result that the displayed image consists of alternating lines from each field. This can create a flicker effect, which some people find distracting. In my case, the said /etc/X11/xinit file doesn’t seem to add any flicker.

Let’s break down the contents of /etc/X11/xinit.

# hide mouse cursor
unclutter --noevents -b

# disable dpms to prevent screen from blanking
xset -dpms
xset s off

# allow coredumps for ES
ulimit -H -c unlimited
ulimit -S -c unlimited emulationstation

# dbus launch is required for the gio/gvfs/trash:///...
eval `dbus-launch --sh-syntax --exit-with-session`

### nvidia ###
nvidia_prime="$(/usr/bin/batocera-settings-get -f /boot/batocera-boot.conf nvidia-prime)"
if test "${nvidia_prime}" = "true"
then
  export __NV_PRIME_RENDER_OFFLOAD=1
  export __VK_LAYER_NV_optimus=NVIDIA_only
  export __GLX_VENDOR_LIBRARY_NAME=nvidia
fi

### NVIDIA ###
nvidia_prime="$(/usr/bin/batocera-settings-get -f /boot/batocera-boot.conf nvidia-prime)"
if test "${nvidia_prime}" = "true"
then
# Set VGA-1 output to 640x480 resolution
# and position it at the top-left corner of the screen
xrandr --output VGA-1 --mode 640x480 --pos 0x0 --rotate normal
  
# Set HDMI-1 output to auto mode, position it at the top-right corner of the screen
# and rotate it normally
xrandr --output HDMI-1 --auto --pos 640x0 --rotate normal
  
# Set environment variables to enable NVIDIA GPU offloading
export __NV_PRIME_RENDER_OFFLOAD=1
export __VK_LAYER_NV_optimus=NVIDIA_only
export __GLX_VENDOR_LIBRARY_NAME=nvidia
  
# Use optirun to start EmulationStation in a 640x480 window on the VGA-1 output
optirun /usr/bin/emulationstation --screensize 640 480 --screenoffset 0 0 --gamelist-view detailed --windowed 1
else
# Start EmulationStation in full-screen mode with a 1920x1080 resolution on the primary display
emulationstation --screensize 1920 1080 --screenoffset 0 0 --gamelist-view detailed
fi

########################
#####-CRT CONFIG-#######
########################
##-Default Resolution-##
########################
xrandr -display :0.0 --newmode "640x480i" 13.10 640 664 728 832 480 484 490 525 interlace -hsync -vsync
xrandr -display :0.0 --addmode VGA-1 "640x480i"
xrandr -display :0.0 --output VGA-1 --mode "640x480i"
########################
########################

openbox --config-file /etc/openbox/rc.xml --startup "emulationstation-standalone"

Classic Games with an Authentic Gaming Experience on Batocera Linux

Using Batocera Linux with VGA output to a CRT monitor, gamers can experience classic arcade and console games as they were meant to be played, with an authentic look and feel that cannot be replicated on modern LCD screens. The use of a CRT monitor adds a sense of nostalgia to the gaming experience and rivals the typical TV sets of the day in terms of console gaming. Furthermore, the hardware modifications required to set up the system, which include CPU upgrades, hard drive installation, and adjustments, can provide a rewarding tinkering experience for those interested in electronics and software. Overall, running Batocera Linux with VGA out to a CRT monitor using the Build-CRT-15KHz-Batocera-V35 script offers a unique and enjoyable gaming experience for classic arcade game enthusiasts and a great opportunity for tinkering with hardware and software. ■