Nexus v0.1b Network Link Program Demo 						26/07/01

Nexus is a Win32 application written to allow the connection of 2 yaroze playstations over the internet (or LAN). It transfers the same type of data packets between playstations as used in the cyclone library , with a few modifications to the playstation code. This is a test version as I havent had the chance to see if it works.

To try the demo over the net, first run one of the auto files from the PAL or NTSC directories depending on your video mode. In PAL auto8p loads the 8 byte packet demo, and auto34p loads the 34 byte packet demo. Make sure the same demo is run on both yarozes.

Next make sure you're connected to the net, then run Nexus.exe. Once it has initialized, click on Settings, and in the Settings box select the following:

Local IP
Address - the network address used for the connection. Make a note of it as you may need to pass it to the other player.
Port - the socket port for the connection. Use the default 3975, if you need to change it make sure the other player knows the new value.

PlayStation Settings
Serial Port - the PC port the yaroze is connected to.
Port Speed - fixed at 115200bps

Debug
High Priority - if checked changes Nexus' task priority from normal to high. the extra CPU time helps prevent other tasks disrupting the connection between PC and yaroze. I've left this as an option as it may not be necessary, but it helps on my PPro 200.

Increase Port Time - if checked increases the time spent waiting for a serial port event to occur, which means Nexus can react immediately if for example the yaroze was sending a data packet. This also means the on screen info won't be updated during a transfer, which is the idea as this can disrupt the connection.

VSync Interval Adjustment - this changes the amount of time the PC waits between sending packets to the yaroze. For PAL the interval is 20 milliseconds, which is a nice round number and should work fine without adjustment. For NTSC the interval is 16.667ms which is a problem as Windows timing functions don't work with values less than 1ms. In Nexus the NTSC interval has been set at 16ms, which means data may be sent to the yaroze too quickly. You'll know if this happens as the message "PlayStation RTS line dropped" will be displayed. If this happens too often change the interval value to 17ms by changing the vsync interval adjustment value to 1. If you get to test this let me know which value is better.


After you've chosen your settings, click OK. The serial port and socket etc are then opened, if no errors occur, the Connect and Listen buttons are enabled. One player should choose to Listen for a connection while the other Connects. The listening player will need to pass their IP address (and port if not 3975) to the other player through something like ICQ. The connecting player then clicks on Connect and enters the other players IP and port. If a connection isn't established within a few seconds then something's gone wrong. The most likely causes are the remote player IP or port are wrong, or one player has lost their connection to the net.

If a connection is established, go back to the yaroze and choose connect, the start transfer. If you can move a box around the screen the connection is working.


What to look out for
If you get this far it would be a minor miracle, but if it does work I'd be interested in knowing the Ping value during the transfer, and also the Diff value on the yaroze screen. In the demo's I've set the maximum difference in frames between the 2 yarozes at 7, which in PAL is a 140ms delay. I'm hoping it'll prove less than that, for 56k modems 100ms or 5 Diff should be the maximum.


Test transfers
To test the demo's on a single yaroze, enter the settings in Nexus as normal, then connect to the IP and port you chose in settings. If you're offline the IP would be 127.0.0.1. Any packets sent from the yaroze will then be sent back to it, so you'll be moving 2 boxes around instead of one.


That's about it for the moment. If you do test it over the net or on a LAN let me know how you get on. If you want to help me test it get in touch.

Thanks,
Peter

hanno@btinternet.com