SNAC: unstable inputs in Gran Turismo 2

[Thelypody]

PSX core: 20240418, Main: 20240505.

While using a genuine DualShock 2 controller connected to MiSTer over SNAC, I encountered an input issue in all versions of Gran Turismo 2. Controller inputs appear to be unstable in main menu, either being doubled or skipped. Additionally, when entering the Options menu and switching to button configurations tab, another issue can be observed. By default steering in game is set to dpad if using digital controls or left analog stick if using analog controls. Enabling Analog mode on DualShock 2 causes the game to constantly switch between dpad and analog stick on steering controls, presumably showing that the game constantly loses connection to the controller for a brief moment.

Tested with the following game versions:

• Gran Turismo 2 (Europe) (En,Fr,De,Es,It) (Disc 1) (Arcade Mode)
• Gran Turismo 2 (Europe) (En,Fr,De,Es,It) (Disc 2) (Gran Turismo Mode)
• Gran Turismo 2 (Japan, Asia) (Disc 1) (Arcade)
• Gran Turismo 2 (Japan, Asia) (Disc 2) (Gran Turismo)
• Gran Turismo 2 (USA) (Arcade Mode) (Rev 1)
• Gran Turismo 2 (USA) (Simulation Mode) (Rev 2)

To make sure that this is not a failure on my hardware end, during the same game session DualShock 2 functioned perfectly with Gran Turismo (Japan, Asia), which makes it more likely to be a particular game issue.

[chanunnaki]

Came here to post about this issue. I experience the same issue with NeGcon controller via MisterFPGA.co.uk SNAC PSX Adapter.

Tried on GT2 Arcade disc (Rev 1) US and Simulation Disc (Rev 2) and both exhibit same issue.

Controller works fine in R4: Ridge Racer and Gran Turismo 1