Network commands are used to control certain parts of RetroArch. To do this, commands are sent to RetroArch via the User Datagram Protocol (UDP).
Usually, in Recalbox, these commands are sent through the Hotkey function of the controller. For example, to reset the game, you press the Hotkey + B keys or to save the game, you press the Hotkey + Y keys.
This only works with RetroArch / emulators that are part of Libretro.
But these commands can also be sent to RetroArch via a command line or GPIO pins. To do this, you need to enable the network commands option in the RetroArch menu or change the following line in retroarch.cfg :
network_cmd_enable = true
You are using an existing retro game console box (NES, N64, etc.) and you want to use the original reset button to reset the game you are currently playing and not to reset the entire hardware (Raspberry Pi, etc.). The following script shows how to send the RESET network command to RetroArch via GPIO pins 5 and 6 to reset the current game.
import RPi.GPIO as GPIO
import time
import socket
# addressing information of target
IPADDR = "127.0.0.1"
PORTNUM = 55355
# enter the data content of the UDP packet
COMMAND = "RESET"
# initialize a socket, think of it as a cable
# SOCK_DGRAM specifies that this is UDP
try:
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
except socket.error:
print 'Failed to create socket'
sys.exit()
GPIO.setmode(GPIO.BCM)
GPIO.setup(3, GPIO.IN, pull_up_down=GPIO.PUD_UP)
def exitEmulator(channel):
s.sendto(COMMAND, (IPADDR, PORTNUM))
GPIO.add_event_detect(3, GPIO.FALLING, callback=exitEmulator, bouncetime=500)
while True:
time.sleep(10)
With this script, it is not only possible to RESET emulators, but you can also use the necessary command from various commands. You can QUIT the emulators (back to EmulationStation), LOAD or SAVE a game state, PAUSE the game, etc. To do this, simply replace the RESET command in the COMMAND = RESET with a command of your choice.
This script may not work with all RetroArch network commands. For some it works, but for others it needs more work to make it work (for example, FASTFORWARD_HOLD).
You can also remap the pins of your Raspberry Pi.
And don't forget: Recalbox already has built-in options to reset, start and stop the hardware you are using via buttons and GPIOs.
The following commands are supported by RetroArch:
You can also send network commands via the command line in Linux. Here's how to do it:
echo -n "QUIT" | nc -u -w1 127.0.0.1 55435
RetroArch is listening on port 55435 by default (the same port as for Netplay).