nesdev.org

I've looked at the firmware and found something that might be the output pin selector. If it is, 72-76 and 97 are the ones that use OUT4. Those are all percussion and sound effects. Begin associated with percussion actually makes sense. OUT4 could potentially be a white noise output. White and Pink...

Harpsichord and Synthesizer [...] the other four sounds Just want to make sure you're aware: Even though there are only 6 instrument buttons, there are 128 total instruments available using special button combinations. If you search for images of the Miracle Piano, you'll see some versions have muc...

I finally had time to probe a few pins inside the Miracle Piano. AS0012 - Pin 21 (PWM) It turns out this pin controls the master volume and NOT the envelope as I had originally assumed. Turning on the keyboard, this pin defaults to about 50%, but as you can see, it is not exactly 50%. How odd. When ...

Whoa, this looks like an excellent game! Nice work.


...also, why is the new topic button directly next to post reply? That is confusing.

Khaz wrote:

Jazzmarazz wrote:At first I wanted to say that it looks like an official post-factory mod, because of the zero Ohm resistor.

... Can someone briefly explain to me why a zero-ohm resistor EXISTS? That just a piece of wire, isn't it?

They exist as jumpers that can be easily placed by pic and place machines.

Alright, thanks! Hey Ice man. The diagram Farid Shared is what I have found existing on most official carts. It works but is not ideal since the carts do not contain a low-power reset IC like more modern carts. This is why Every battery backed cart for the NES demands that you hold the reset button...

Joe wrote:

Jazzmarazz wrote:Back on page 2 someone was asking to have it desoldered.

Yes, that was me.

Great! So does that one contain the sound samples? How are they arranged? Are they 8-bit, 16-bit or something else? I am very interested in those.

thanks joe

I have been reviewing the public schematics and am interested in the sound portion and would like some information on some of the pins such as "OUT1, OUT2, OUT3 and OUT4" of the J004 IC as well as the "PWM" pin of the AS0012. OUT1 through OUT4 are outputs of the J004 DAC. While ...

At first I wanted to say that it looks like an official post-factory mod, because of the zero Ohm resistor. No one uses those, so it looks legit, but these two pins are p00 and reset. if I am not mistaken, the bridge could potentially reset the console unexpectedly but I assume it works or you would...

So the PWM is in fact being used as the envelope generator? That is a really cool technique and I am surprised to find that it is that old. I have seen the technique used on many microcontroller projects recently so I had just assumed it was a more recent concept.

Glad that some new info has showed up! The two ROMs are not directly interchangeable, since the '61 board rearranges some of the address and data pins relative to a standard EPROM pinout. I descrambled the 2.03 ROM (thanks, Farid) to compare it to 1.10, and the two are clearly based on the same cod...