Problem with HDMI and RCA

Composer

Hello everyone;

Im in a project that consist on put a Raspberry Pi 4B in a PS1 case. And i wanna use the HDMI port and the RCA port.

Now i can get image with the RCA with a 240p resolution, but when i reboot the raspberry with the HDMI plugged and the RCA unplugged i didn't recieve any image.

I have a mini Jack to females RCA and a microHDMI to male HDMI and a Female HDMI to Female HDMI connected.

Any help??

Os paso mi archivo config.txt

This is my config.txt

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
overscan_left=16
overscan_right=16
overscan_top=16
overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
framebuffer_width=352
framebuffer_height=240

# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=2
#hdmi_mode=4

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
config_hdmi_boost=4

# uncomment for composite PAL
enable_tvout=1
#sdtv_mode=0
sdtv_aspect=1
sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
#dtoverlay=vc4-fkms-v3d
overscan_scale=1

Thank you!

mitu

@Composer said in Problem with HDMI and RCA:

# uncomment for composite PAL
enable_tvout=1

Remove/comment the line above and the HDMI output should work.

Composer

@mitu said in Problem with HDMI and RCA:

@Composer said in Problem with HDMI and RCA:
# uncomment for composite PAL
enable_tvout=1
Remove/comment the line above and the HDMI output should work.

But when i comment this line i cant use the RCA.

I need to use the HDMI and when i disconnect the HDMI i need to use the RCA without edit the config.txt file.

Thanks for the quick answer!

mitu

That's not possible on the Pi4 - it worked on previous models though. On the Pi4, you need to explicitly enable the analog output, since it's disabled by default:

Cf. https://www.raspberrypi.org/documentation/configuration/config-txt/video.md:

On the Raspberry Pi 4, composite output is disabled by default, due to the way the internal clocks are interrelated and allocated. Because composite video requires a very specific clock, setting that clock to the required speed on the Pi 4 means that other clocks connected to it are detrimentally affected, which slightly slows down the entire system. Since composite video is a less commonly used function, we decided to disable it by default to prevent this system slowdown.

Composer

@mitu said in Problem with HDMI and RCA:

That's not possible on the Pi4 - it worked on previous models though. On the Pi4, you need to explicitly enable the analog output, since it's disabled by default:

Cf. https://www.raspberrypi.org/documentation/configuration/config-txt/video.md:

On the Raspberry Pi 4, composite output is disabled by default, due to the way the internal clocks are interrelated and allocated. Because composite video requires a very specific clock, setting that clock to the required speed on the Pi 4 means that other clocks connected to it are detrimentally affected, which slightly slows down the entire system. Since composite video is a less commonly used function, we decided to disable it by default to prevent this system slowdown.

oh... i see, there is a fix or workaround to do that i need?

mitu

@Composer There's no fix - you'll have to workaround having different configuration files or using some conditional configuration.

You can have 2 different files - one for RCA and one for HDMI video output - and switch between them with a pair of scripts that you can call from the RetroPie menu. You can drop any .sh script in $HOME/RetroPie/retropiemenu and they'll appear in the RetroPie menu in EmulatonStation, you can execute the script (that switches the configuration) and then reboot.

A conditional config.txt could also work. One method that might work is to have flip switch that you can toggle to activate a GPIO pin, then you can put the enable_tvout option behind this GPIO condition

[gpio4=1]
# Settings here are applied if GPIO 4 is high
enable_tvout=1
[all]
enable_tvout=0

If you decide on this approach, I'd encourage you to ask in the Raspberry PI forums for confirmation that it would work - I haven't tested it.

Composer

@mitu Ok i see...
To use the GPIO i need to connect the switch to a GPIO that give 5v right?

And to have a workaround.... can i have a menu like another emulator that give me the option to run a script to change the config file?

Thank you!

mitu

@Composer said in Problem with HDMI and RCA:

@mitu Ok i see...
To use the GPIO i need to connect the switch to a GPIO that give 5v right?

Probably one of the ground pins.

And to have a workaround.... can i have a menu like another emulator that give me the option to run a script to change the config file?

Yes, I just explained that in my previous post.

Composer

@mitu Oh Sorry!!
My english is very bad jaja.

So.. im gonna to try the scripts and when i have a switch im gonna try it connecting it to ha 5V and ground GPIO.

Thank you so much!