8 direction diagonal movement difficulties

[raidho36]

Just get yourself a new USB keyboard, it'll cost around ten bucks or something.

[verilog]

Keyboard ghosting, perhaps?
The article explains what might be the problem, be sure to check out the keyboard application at the top of the page! For example, press 'A', 'Z' and then 'X'. Now, press 'Z', 'X' and then 'A'.

[Bobbias]

PS/2 port has legacy-related issues with bandwitdh or something, I never went into details too deep, but the sympthoms of that is that if you can't have more than specific amount of keys pressed simultaneously. Hell knows what logic picks first few that pass, the rest are ignored (and buffer overflow signal is sent, this normally results in PC speaker short beep).

Actually, PS/2 connections are superior to USB connections as far as n-key roll over is concerned. USB can handle a maximum of 6 keys (without some workarounds, I've heard of companies who claim full 26-key roll over or something on USB (possibly with multiple connections))

The big issue is that on standard keyboards (aka anything less than $100+) the real limiting factor is the layout of the key grid. There are some situations where multiple key presses are undetectable. Go read up on rollver on wikipedia.

[bdjnk]

Hey, thanks verilog and Bobbias!

I also found some good information in this discussion.

I guess my keyboard is just cheap as hell. Time to get a better one.

[T-Bone]

On some older keyboards, I've found that WASD works much better than the directional keys when it comes to this. Not sure why.