File talk:Neswires.jpg
It looks to me like the diagram for the RF Famicom (the description says NES, but I think it is clearly the RF Famicom, not the NES). I find this very helpful to me! It seems the audio from the microphone is also send to the cartridge, together with the square/triangle/noise/DPCM (does any mapper use this?), and now I can also see exactly how the expansion port is wired. It could help with many things, including to make a hardware clone (including one with a microphone). I suppose it means the device on the expansion port could read the inputs from the second controller, and I suppose as well as the expansion port to trigger IRQ, it can be used to communicate another signal directly between the expansion port and the cartridge. (If making a hardware clone, I suppose we can program the CPU, APU, PPU, and possibly some other components in Verilog, and then wire other things using discrete components, so it resembles this diagram; however, NES controller ports can then be added, and the microphone could be connected to an extra port. Of course, I suppose things like the Visual2A03 and so on can also help when making a hardware clone.) --Zzo38 (talk) 12:55, 22 May 2013 (MDT)
What are the direct output levels of the AUX A and AUX B of the 2A03 and video of the PPU (ignoring any resistors/etc which aren't in the IC)? What is the output level and impedance of the microphone (again, ignoring the resistors and so on shown in the schematic)? --Zzo38 (talk) 00:52, 26 May 2013 (MDT)
- Output levels of the PPU are known: NTSC video. Otherwise, I can only give you ranges: the expected input impedence from the microphone is 5kΩ or less. Typical electric microphones have an impedence around 1-2kΩ, but the famicom amplifies it: http://atariusa.com/Famicom_Schematics/FC%20Control%20Pads%204021B%20RF%20and%20Power%20Schematics.png . The output of the 2A03's audio stage doesn't have a canonical voltage because it's a current-mode device: in the absence of the external 100Ω resistors it will "output" 5V always. —Lidnariq (talk) 12:18, 26 May 2013 (MDT)
Remark: this image was apparently modified to depict the NES rather than a Famicom, as evidenced by the fact that the cart connector along the right edge shows pin numbers counting up to 72 (and the Famicom-only pins no longer have numbers on them) and some other chip pin numbers were sloppily edited. --Quietust (talk) 11:46, 8 August 2023 (UTC)
