Search found 308 matches

by creaothceann
Sun Apr 18, 2021 9:18 am
Forum: SNESdev
Topic: Need guidance with nes to snes.
Replies: 247
Views: 28442

Re: Need guidance with nes to snes.

Interrupts push the status register to the stack, so in your interrupt handler(s) you could just clear the 16-bit mode bits with SEP #$30. (%00110000)
by creaothceann
Wed Apr 14, 2021 11:10 pm
Forum: SNESdev
Topic: Need guidance with nes to snes.
Replies: 247
Views: 28442

Re: Need guidance with nes to snes.

Does the scrolling speed depend on the CPU speed? Because the NES and the SNES have the same field-/framerates, but the SNES runs at up to ~3.58 MHz, depending on which area the CPU is accessing.
by creaothceann
Sun Apr 11, 2021 1:56 pm
Forum: SNESdev
Topic: About audio in rom bandwidth capabilities, and a external cpu...
Replies: 12
Views: 757

Re: About audio in rom bandwidth capabilities, and a external cpu...

That's how the SGB does its extra audio effects with Donkey Kong, afaik.
by creaothceann
Fri Apr 09, 2021 3:50 am
Forum: SNESdev
Topic: Need guidance with nes to snes.
Replies: 247
Views: 28442

Re: Need guidance with nes to snes.

It doesn't care what the sounds you play back are, could be music or sfx. You can only play one track at a time though.
by creaothceann
Fri Apr 09, 2021 12:27 am
Forum: SNESdev
Topic: SNES oscilloscope readings?
Replies: 30
Views: 1729

Re: SNES oscilloscope readings?

As lidnariq said, slower signals like the CPU address/data buses, can be sampled with cheaper logic analyzers. Higher-frequency signals would be more difficult.

More theory:
https://www.youtube.com/watch?v=dobU-b0_L1I
https://www.youtube.com/watch?v=xZ5wKYnCNcs
by creaothceann
Thu Apr 08, 2021 7:59 am
Forum: SNESdev
Topic: SNES oscilloscope readings?
Replies: 30
Views: 1729

Re: SNES oscilloscope readings?

Unfortunately only the S-PPU (5C77-01) and various cartridge co-processors are decapped so far, while the S-CPU, S-APU and S-WRAM are not yet, AFAIK. 65c816: https://commons.wikimedia.org/wiki/File:WDC_W65C816_top_metal.jpg 5A22: https://siliconpr0n.org/map/nintendo/s-cpu-a/mz_ns20x/#x=8752&y=8872&...
by creaothceann
Thu Apr 08, 2021 3:29 am
Forum: SNESdev
Topic: SNES oscilloscope readings?
Replies: 30
Views: 1729

Re: SNES oscilloscope readings?

It would be easier to transplant a CPU from another SNES...
by creaothceann
Wed Apr 07, 2021 4:02 am
Forum: SNESdev
Topic: SNES oscilloscope readings?
Replies: 30
Views: 1729

Re: SNES oscilloscope readings?

USB 3 can deliver more, but then you need the entire chain to be USB 3 - plug, cable and device.
by creaothceann
Mon Apr 05, 2021 12:16 pm
Forum: SNESdev
Topic: Need guidance with nes to snes.
Replies: 247
Views: 28442

Re: Need guidance with nes to snes.

dougeff wrote:
Mon Apr 05, 2021 8:42 am
Another option. MSU1. It's sort of a fictional chip that plays MP3 files. Lots of emulators will play MP3 files along side the game.
Afaik PCM files with a special header. (@infidelity: MSU1 is also implemented in the SD2SNES cartridge)
by creaothceann
Sun Apr 04, 2021 4:05 pm
Forum: SNESdev
Topic: Revision 2021 SNES Demo
Replies: 6
Views: 920

Re: Revision 2021 SNES Demo

by creaothceann
Sun Apr 04, 2021 12:08 pm
Forum: SNESdev
Topic: SNES programming Videos
Replies: 30
Views: 4960

Re: SNES programming Videos

I always thought the extra vblank time is because the frame-rate is slower on PAL, 50 instead of 60 Hz PAL frame rate is lower than NTSC, and the extra time is used to draw more lines (625 instead of 525). You get the most extra VBlank time when not enabling overscan mode (224*2 instead of 239*2 li...
by creaothceann
Sat Apr 03, 2021 10:25 am
Forum: SNESdev
Topic: Need guidance with nes to snes.
Replies: 247
Views: 28442

Re: Need guidance with nes to snes.

infidelity wrote:
Sat Apr 03, 2021 5:56 am
I was fully prepared for things like this to pop up, since jts a double whammy of being new to snes, and doing a port as well.
It's not a bad thing, since the best way to learn something is to already have a definitive goal.
by creaothceann
Fri Apr 02, 2021 1:19 pm
Forum: SNESdev
Topic: Need guidance with nes to snes.
Replies: 247
Views: 28442

Re: Need guidance with nes to snes.

This video may be useful as a reference.