Enabling 5200 joystick input

[+Ryan Witmer]

Hello, amateur 5200 assembler here with some input problems.

 

I'm currently trying to write a simple program that just places a sprite on the screen that can be manipulated with the joystick. I have this working perfectly via an emulator, but when I run my code on an actual console, I only get 0s from the joystick.

 

After doing tons of research, I think I must be missing some sort of enabling bit somewhere that just isn't handled correctly in the emulator. I learned that I need to set bit 2 of CONSOL, and I've done this, but I must be missing something else.

 

Are there any flags that need to be dealt with to get joystick input, and if so, what are they?

[Rybags]

5200 uses the POTn registers on Pokey for the stick directions, so a POTGO sequence is needed each VBlank.

 

I'm not sure if that's done automatically by the 5200 BIOS, but it should be documented somewhere.

[+Ryan Witmer]

5200 uses the POTn registers on Pokey for the stick directions, so a POTGO sequence is needed each VBlank.

 

I'm not sure if that's done automatically by the 5200 BIOS, but it should be documented somewhere.

 

The documentation I found says that POTGO is fired by the default VBI routine, which I haven't changed. Just to be on the safe side, I tried doing it manually in my code, but to no avail.

 

I can't seem to find any sample source that illustrates joystick input. I guess I just need to keep looking.

[+Ryan Witmer]

I found the answer to this. I needed to enable bit 1 in the SKCTL register. Everything is happy now.