nesdev.org

I have a scope, but now I'm looking for a logic analyzer. I'm not sure what I'm looking for, really. What are some recommendations for entry level (this is for 8/16bit retro consoles with signals probably in the 20-50mhz range). What should I aim for and what should I stay away from?

Bit 2 puts the VCE in alternating mode where one frame is 263 scanlines and the other is 262. This has the effect that color burst phase is not reset because it's allowed to invert on the next frame. So frame one has even/odd colorburst phase cycling per scanline, and the next frame is odd/even. Fo...

I knew it from talking with Charles MacDonald; I was working on a project to get the arcade shinobi rom running on the Genesis (years ago). I was trying to replace the graphics routines with custom ones.

Also setting bit 2 applies some kind of artifact correction to the picture, and that also only affects the composite signal, or at least it's only visible on it since I suppose there's no NTSC artifacts on RGB. Setting the bit makes text easier to read on my TV, but I see no difference at all on em...

Or.. you know.. hack the original SMB hack to run on a PC-Engine for bigger sprites, more color, more ram, four time the speed. https://www.youtube.com/watch?v=5i48xMQX7NI <- Megaman NES rom running on the PC-Engine with a few sprites upgraded (color and size). Or the PC-Engine Supergrafx with even ...

Are the lines parallel to the x/y axis? In one instance, yes ( think of a line with any angle going through a bounding box) Are these infinite lines, or line segments with defined start and end points? Is either line completely static, where its slope and position won't ever change? Angle is arbitr...

I'm pretty sure quite a number of MD games use 3bpp to do exactly what you're saying; 4 subpalettes now becomes 8. Or a combination of 4bbp and 3bpp (shifted and non shifted). But yeah, it's not as fast to do in realtime writing to VRAM like with planar, but then again MD uses VDMA anyway. A lot of ...

Ah! My bad, you are right. Both $xA and $x9 does the same thing. Only SM has two different types of 2-dot width modes. But I think it isn't the LSbit of the Y-coordinate but the LSbit of the PC (Pattern Code, AKA "name") of the sprite data that decides which set of pattern data to use. Ot...

Yeah, both SNES and MD can update almost the exact same fraction of the screen worth of tiles via DMA during VBlank (which console can do more depends on how much of OAM/SAT and CGRAM/CRAM need updating, as they are different sizes). Mega Drive can keep going during active display using the FIFO, b...

Yeah thanks, I saw that, it's from one of the linked threads. I finally joined that forum since the PCEngineFX forum was apparently destroyed by spammers and the English PC Engine community was split in two. OK so 2-dot mode for the hi-res mode it is. There are two access width settings though. VM ...

The SNES, in general cases, has the worse sprite setup of the SNES, TG16, Genesis. Genesis is clearly superior to both (H40 mode). Have you guys actually played Genesis games?! In order for the SNES to compete with the Genesis, you'd have to use 8x8 paired with 16x16 mode. And you'd burn through tha...

Yeah. Best to use 2 dot access for 512 mode (10.7mhz), and you won't get sprite scanline dropout either. Here's a chart made by elmer that shows how using a 2-dot access in mid-res mode can affect your sprites: Screen Shot 2019-11-01 at 8.54.03 AM.png The US localization of Rtype potentially has mor...

Genesis has the SNES beat in the sprites department overall. Flexibility of sprites in ram vs the snes bank layout really comes into play when you need more unique detail on screen via sprites (instead of just the same reference). It allows better option for more frames in vram without always upload...

but C is actually Q and I simply added. So VCE actually outputs Y, Q, and I separately and it's mixed before the amp. It emits modulated U and V components? Yeah. If you can demodulate U and V outputs, you can do a component setup. I cut the traces to U and V amp circuit and fed just Y+sync (well, ...

You can disable the channel without resetting the waveform pointer. Also you don't have to turn off the channel to write updates to it. You can write updates to it while it's playing and the current pointer position will get over written. A few games do this to get a steal-y sounding timbre change. ...