#RETROLINK NES CONTROLLER CIRCUIT BOARD SERIAL#

Let me repeat that again, because it shocked me so much: You can write a byte to PPUSTATUS and read it back from PPUADDR. And FCEUX already emulates this accurately. which are writable, as well as like PPUSTATUS ($2002). This gives full control of $4016 open bus through a $3F16-$4016 sequence, so long as you're not on a cart with pull-ups. If you write to pretty much any PPU register and then read from the nominally write-only register PPUADDR ($2006), you get the same byte back. But I seem to remember reading that some clone controllers have a string of 0's, as if the 4021's shift input were tied to power.ĮDIT 45 minutes later with additional observations, performed on a PowerPak: It'd be more convenient for me to assume that return a string of 1's after the report like the official controllers do, a consequence of the 4021's shift input being tied to ground. Later on, as I make the test ROM more detailed, I'd also like to get results from a variety of unlicensed NES controllers. I'd like to get results from some Famicoms, especially with controllers that plug in to the DA15 port. I'll post a revised test program tomorrow.

There's a bug in my test program that makes the fourth and eighth bytes in 'Controller bits' useless.

Per lidnariq's result, the PPU might not really have open bus.The original rectangular NES controller, the Famicom AV dogbone, and the top-loading NES dogbone appear to behave the same.But with a 'real' cartridge, however, APU open bus behaves as expected. Open bus on a PowerPak is pull-ups to $FF.

#RETROLINK NES CONTROLLER CIRCUIT BOARD SERIAL#

I can tell a serial input (like the standard controller, Super NES Mouse, Power Pad, or Arkanoid knob) from a constant input (like the Zapper trigger or the Arkanoid button).

I wonder whether running the FDS version of The Legend of Zelda on a PowerPak would cause Pols Voice to self-destruct.

D0-D4 of both ports drive 0 on a front-loader, but D2 of port 1 on a top-loader is open bus.

Retrolink nes controller circuit board