On the NES, is there a reliable way to distinguish a controller on port 2 from an empty port 2?
My current project is a 2-player alternating card game. Because a lot of NES owners I've met (as well as PC emulator users) have only one working controller, I want my game to work whether one or two controllers are plugged in. I've noticed that Super Mario World for Super NES reads Luigi's keypresses from controller 1 if controller 2 is not present. I've also noticed that PS1 and PS2 games pause when the player unplugs a controller (e.g. "YOU ARE ROCKING OUT A BIT TOO HARD" in Guitar Hero III), and all three Super Smash Bros. games autodetect plug-ins and plug-outs (even when the N64 console's manual suggests not plugging except with the power off).
My current project is a 2-player alternating card game. Because a lot of NES owners I've met (as well as PC emulator users) have only one working controller, I want my game to work whether one or two controllers are plugged in. I've noticed that Super Mario World for Super NES reads Luigi's keypresses from controller 1 if controller 2 is not present. I've also noticed that PS1 and PS2 games pause when the player unplugs a controller (e.g. "YOU ARE ROCKING OUT A BIT TOO HARD" in Guitar Hero III), and all three Super Smash Bros. games autodetect plug-ins and plug-outs (even when the N64 console's manual suggests not plugging except with the power off).