Latest upload by: TiagoSC
20th January 2023

PlayStation Development - Common Questions

Revision 1.4

NOTE: The PSX Blaster is still in development and is not available at this given time.

How do I make PlayStation 1 games?
To get started making PlayStation 1 games, please start off by installing the Psy-Q SDK as per the setup document here.

The requirements needed to make PlayStation 1 games are a PlayStation 1 (a PSX preferably with a Serial (SIO) and Parallel Port (PIO) (IE: PSX models SCPH-550x, 750x)), a Windows PC (32-bit), and a Communications Link (Comms Link) device (such as the PSX Blaster) or PSXSERIAL adaptor. However, an emulator will suffice okay in most situations as a substitute for a 'Comms Link' device, but wont be as fast to use or be as accurate as the real hardware.

There are also the official Sony development boards, such as the DTL-H2000, DTL-H2500 and STL-H2700. The H2000 is the best and generally cheapest card to buy, but will require an old motherboard with two ISA 16-bit slots, and Windows 98. The good thing about these cards is, they have an additional 6MB of RAM, giving you a total of 8MB compared to the standard 2MB shipped in all PlayStation 1 consoles. The advantage of the additional RAM is that you have a lot more address space to upload your images and data to, thus not requiring you to burn and waste several CD-ROM's. Another great feature with the official development boards by Sony is that you get to use DBUGPSX.EXE for live, step-by-step debugging in C (as well as ASM).

Please note however, that we have managed to hack a PSX console to use 8MB of RAM, so the DTL-H2000 is only good for debugging.

Do I need a Net Yaroze to make PlayStation 1 games?
Absolutely not! You just need a standard grey PlayStation 1 (PSX) with a Parallel Port (PIO) or Serial port (SIO), a PC running Windows (32-bit) and a 'Comms Link' device such as the PSX Blaster, or PSXSERIAL adaptor. As mentioned above, you can also just use a PSX emulator running your computer such as PSXFIN or ePSXe.

The Net Yaroze was just a low end hobbyist version compared to the high end developers version that is the SDK, Psy-Q. The Net Yaroze had the exact same RAM that standard PlayStation's had (2MB). The only difference is the Net Yaroze could play region free (IE: you could play NTSC games on a PAL Yaroze). However, it could not run copied discs unlike the Sony Debuggers. The Net Yaroze also required a set of libraries to reside in RAM, thus reducing your overal RAM storage. A PlayStation modchipped that has a PSXSERIAL cable will suffice as a direct and even better replacment to the Yaroze.

What Communications Link device is the best to use?
A PSX Blaster is the best option, but older alternatives such as an Xplorer running CAETLA is just as good too. Though, compared to the PSX Blaster, the Xplorer requires a Parallel Port (LPT) port on your computer with SPP mode support to work (as well as Windows 98). Another alternative is the PSXSERIAL adaptor which plugs into your PlayStation 1 serial port. Also note that since the PSX serial port is literally a RS232 port at 3.3V, it can only run at a maximum baud rate of 115200 (so it is very slow compared to the PSX Blaster and Xplorer). If you have a PSone, you can solder the PSXSERIAL adaptor directly to a PSone motherboard and develop games using a PSone should you not have an original PlayStation 1.

Is it legal to program the PlayStation 1 using Psy-Q?
We should start off by saying that Sony does not do anything anymore with the PlayStation 1, and that they have moved away from it as it has made them their money. Some will say that Psy-Q can be actually classified as abandonware as the copyright's have ran out, and that Psygnosis is long gone. Problem is though, that SN Systems is still in business with Sony. In our opinion, it is okay to use the Psy-Q SDK, but just be sure you don't start selling your game in stores, and also be sure to not put any 'Sony Licensing' text in the game (IE: "Sony Computer Entertainment Presents"), on the games case, manual, etc. Placing the text "Not Licensed by Sony" in the game copyright on boot should be done. It would also be a good idea to give thank's to Sony, SN Systems and Psygnosis in your credits.

So how did we get the Psy-Q SDK you ask? Well someone leaked it many, many years ago onto the Internet. We grabbed it, cleaned it up, and hosted it for free so that anyone who has a passion for the PlayStation 1, can make anything they wish. There are also direct 1:1 copies of Sonys official Programmer Tools CD-ROM.

In all honesty, Sony is not going to care if you program and learn from their PlayStation 1.

Is it legal to program for the Net Yaroze?
There is another problem here. Sony only allowed the users who actually purchased the kit to be a licensed developer, as you had to sign some papers during the purchase process (This is how you got your membership card). The problem there though, is that Sony does not support the Yaroze at all anymore. There is no way to get hold of Sony and ask them to register your Yaroze, as Sony shut down the Yaroze site a few years ago.

The Yaroze SDK is also just a stripped down version of Psy-Q, missing tools, and important documents. The Net Yaroze by today's terms, is nothing more than a collectors console. If you are really serious about programming the PSX, you can download the Psy-Q SDK, and use it on any normal PlayStation 1, providing you have a PC and a 'Comms Link' device. It is suggested however, that you read the Net Yaroze documents, as the hardware is exactly the same and the same programming rules apply to the standard PlayStation 1.

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