Search found 469 matches

by Joe
Thu Jun 17, 2021 4:21 pm
Forum: NESdev
Topic: Somebody is selling my game
Replies: 13
Views: 801

Re: Somebody is selling my game

If you haven't given them a license to distribute your copyrighted material, what they're doing is illegal.

They might be willing to talk about it though. You can try contacting them before you start getting lawyers involved.
by Joe
Sat Jun 12, 2021 7:57 pm
Forum: Newbie Help Center
Topic: Questions About DPCM and PCM
Replies: 21
Views: 1990

Re: Questions About DPCM and PCM

I find it odd that it works if I put it before turning on the screen but not after. It's not odd at all. Right around where you turn on the screen, you also enable NMI. Your NMI handler doesn't preserve the contents of A/X/Y, so whatever code it interrupts will suddenly have different values in the...
by Joe
Tue Jun 01, 2021 9:37 am
Forum: Newbie Help Center
Topic: Creating a data structure.
Replies: 33
Views: 2735

Re: Creating a data structure.

I don't know C well enough to know what i am doing wrong... It sounds like you're building it inside the msys2 shell instead of the mingw32 or mingw64 shell. Each shell is associated with a specific toolchain, and the msys2 toolchain is dependent on msys2. The mingw32 and mingw64 toolchains produce...
by Joe
Mon May 31, 2021 10:53 am
Forum: Newbie Help Center
Topic: Creating a text box
Replies: 31
Views: 2732

Re: Creating a text box

I'm aware that the vBlank box is unchecked, that might have something to do with it. Only thing is any time I load $2002 the debugger shows the NES as having exited vBlank and I don't think that's how it works. The Vertical Blank checkbox reflects the state of the vertical blank flag in the PPU. Tw...
by Joe
Fri May 21, 2021 9:08 pm
Forum: Newbie Help Center
Topic: How should I code this?
Replies: 4
Views: 2072

Re: How should I code this?

Sorry for the title, don't really know what to call the thing I'm trying to do. Arctangent? If you have to pass these numbers to the function through memory, you might be able to leave their original values in memory and perform the comparisons after you've finished the calculations. Without seeing...
by Joe
Sat May 08, 2021 1:40 am
Forum: NES Hardware and Flash Equipment
Topic: A hypothetical MMC3-like mapper without a CPLD
Replies: 4
Views: 3541

Re: A hypothetical MMC3-like mapper without a CPLD

This is just for fun. You wouldn't build this thing if you're worried about how much it costs.

Although, you could replace the four 74*670 with eight 74*373 (or 74*573), a couple of 74*139, and... two 74*04, I think? Spend the money you save on cheaper parts to get a bigger board to hold all of them.
by Joe
Fri May 07, 2021 12:49 pm
Forum: NES Hardware and Flash Equipment
Topic: A hypothetical MMC3-like mapper without a CPLD
Replies: 4
Views: 3541

A hypothetical MMC3-like mapper without a CPLD

Reading about mapper design had me wondering just what it would take to build something like the MMC3 using only new DIP ICs. Turns out it's pretty easy once you have a GAL16V8 . PRG and CHR bank registers can be handled by a bunch of 74*670s. A single *670 can give you four 8KB PRG banks out of a 1...
by Joe
Sat May 01, 2021 5:37 pm
Forum: Reproduction
Topic: SNES VHDL mappers for CPLD
Replies: 3
Views: 2737

Re: SNES VHDL mappers for CPLD

Aren't SNES cartridge mappers pretty simple? If you're using 5V ROMs, you might be able to use a smaller 5V-tolerant programmable logic device, like the ones lidnariq suggested in this post.
by Joe
Thu Apr 29, 2021 8:33 pm
Forum: Newbie Help Center
Topic: Making a cart from scratch...
Replies: 75
Views: 26170

Re: Making a cart from scratch...

Is the AX5202P draining the battery? The wiki claims it's possible. If this is what's causing the problem, you'll see it as unusually high voltage drop across one of the resistors even with the RAM completely removed from the board. (I don't know how to check it without removing the RAM. I also don'...
by Joe
Sat Apr 17, 2021 8:09 pm
Forum: NES Hardware and Flash Equipment
Topic: Hitex HT-767 - interesting famiclone
Replies: 5
Views: 3788

Re: Hitex HT-767 - interesting famiclone

My guess is it was meant to be a 4011 to make a NMI delay circuit for compatibility with NTSC games on a PAL PPU, except they accidentally routed VCC to pin 12 instead of pin 14.
by Joe
Sun Apr 11, 2021 9:43 pm
Forum: NES Hardware and Flash Equipment
Topic: Famicom Network System (aka Famicom Modem) Investigations
Replies: 161
Views: 134256

Re: Famicom Network System (aka Famicom Modem) Investigations

That all sounds awfully familiar.

Have you found any other functions that can be enabled or disabled by writing $412F? (Could there be a similar register in the RF5C66?)
by Joe
Tue Apr 06, 2021 7:30 pm
Forum: NES Hardware and Flash Equipment
Topic: Famicom Network System (aka Famicom Modem) Investigations
Replies: 161
Views: 134256

Re: Famicom Network System (aka Famicom Modem) Investigations

Joe: how on earth did you ever make the connection from $4100/4101/4102 writes to the NMI handler? I found the code for dialing numbers. For pulse dialing in particular, it expects a NMI each time it disconnects or reconnects the line, and it has lookup tables it uses to pick values to write to $41...
by Joe
Sun Apr 04, 2021 6:49 pm
Forum: NES Hardware and Flash Equipment
Topic: Famicom Network System (aka Famicom Modem) Investigations
Replies: 161
Views: 134256

Re: Famicom Network System (aka Famicom Modem) Investigations

For the RF5A18 input signals from the modem module, I was very surprised not to find a signal that reflected whether there is a dial tone or not. The MSM6827L has a call-progress tone detector (bit 1 of DR) that can detect tones between 350Hz and 620Hz. I can't say for sure since I haven't looked t...
by Joe
Fri Apr 02, 2021 8:34 pm
Forum: NES Hardware and Flash Equipment
Topic: Famicom Network System (aka Famicom Modem) Investigations
Replies: 161
Views: 134256

Re: Famicom Network System (aka Famicom Modem) Investigations

tepples wrote:
Fri Apr 02, 2021 8:25 pm
Identity of "Joe" has been confirmed. Try editing now.
Thank you, it looks like I can edit pages now.
by Joe
Fri Apr 02, 2021 8:06 pm
Forum: NES Hardware and Flash Equipment
Topic: Famicom Network System (aka Famicom Modem) Investigations
Replies: 161
Views: 134256

Re: Famicom Network System (aka Famicom Modem) Investigations

Would you mind editing the wiki with your findings? I would like to, but I can't figure out how to get access to edit pages. So [key 0] is not even used in calculating the checksum? Not in command 7C/7D/7E/7F. It does contribute to the CRC-16 calculation in command 12. (And looking again at my note...