Search found 991 matches

by Jeroen
Tue Sep 15, 2020 5:11 pm
Forum: NESdev
Topic: Sprites will not show up
Replies: 12
Views: 418

Re: Sprites will not show up

bit $2002 @loop: bit $2002 bpl @loop lda %10010000 sta $2000 in every known location of running code. its almost laughable at this point, it just won't turn interrupts on no matter what. Is there anything you can think of that I am missing? Thnx for your help, this is so weird You're missing a # si...
by Jeroen
Tue Sep 15, 2020 12:27 pm
Forum: NES Hardware and Flash Equipment
Topic: Reverse Engineering the CIC
Replies: 436
Views: 224726

Re: Reverse Engineering the CIC

Yes that is a point I hadn't considered. In that case however, I still think the Arduino can be a good platform, just don't use the Arduino libraries. Since it's cheap and readily found (There's bound to be lots of info on "bare bones" Arduino programming.) edit: I forgot to mention, obviously the a...
by Jeroen
Tue Sep 15, 2020 12:18 pm
Forum: NES Hardware and Flash Equipment
Topic: Reverse Engineering the CIC
Replies: 436
Views: 224726

Re: Reverse Engineering the CIC

Alternatively you can use an Arduino Uno. They're really cheap, and they have a lot of documentation for newbs.
by Jeroen
Mon Sep 14, 2020 7:44 am
Forum: NES Hardware and Flash Equipment
Topic: Reverse Engineering the CIC
Replies: 436
Views: 224726

Re: Reverse Engineering the CIC

At long last, the trick to entering the ROM dump/debug mode of the SM590 was figured out earlier today by Sean Riddle: http://www.seanriddle.com/sm590/ specifically http://www.seanriddle.com/sm590/sm590dump.txt We now have electronic dumps of: 3193A 6113 non-A (which matched the dump done by neviks...
by Jeroen
Sun Sep 13, 2020 12:26 pm
Forum: NES Hardware and Flash Equipment
Topic: AV Famicom exhibiting ghost inputs
Replies: 9
Views: 483

Re: AV Famicom exhibiting ghost inputs

Just for the record, you're using a pal controller on an ntsc unit? (There's some compatibility issues with the reverse) The fact that it's both controllers worries me, as they have little in common other than the CPU. Which would suggest a damaged CPU. Do you have any measuring instruments like an ...
by Jeroen
Sat Sep 12, 2020 10:54 am
Forum: NES Hardware and Flash Equipment
Topic: AV Famicom exhibiting ghost inputs
Replies: 9
Views: 483

Re: AV Famicom exhibiting ghost inputs

This is just a quick theory as I don't have a lot of time to dive into it: https://console5.com/techwiki/images/7/72/NES-001-Schematic---Controller-Ports.png This is the nes controller port schematic, if some of the diodes DA1, DA2 etc went short circuit, it could be that when the controller pulls d...
by Jeroen
Fri Sep 04, 2020 3:18 pm
Forum: NES Hardware and Flash Equipment
Topic: 3193 vs 3193A chip?
Replies: 5
Views: 454

Re: 3193 vs 3193A chip?

Try not pushing your games down. I've noticed sometimes when the connector pins are bent up too much they stop working in the down position.
by Jeroen
Sat Jul 18, 2020 4:21 pm
Forum: NES Hardware and Flash Equipment
Topic: Standardizing symbols for PCB mirroring pads
Replies: 34
Views: 5129

Re: Standardizing symbols for PCB mirroring pads

How about this? The dot indicates nametable 1, much like in engineering where it shows where pin 1 on an IC is. Edit: These are non-graphical, so at any line thickness: Vertical Mirroring: Two horizontal lines, dot in upper left corner. Horizontal Mirroring: Two vertical lines, dot in upper left co...
by Jeroen
Sat Jul 18, 2020 3:12 am
Forum: NES Hardware and Flash Equipment
Topic: CPU clock madness
Replies: 4
Views: 933

Re: CPU clock madness

1) First thing that always bothered me is that trying to preview CPU's input clock with scope always made the console stop working. Scope has 10M impedance and should almost not affect the circuit. 10x Scope probes have very high resistance, but they actually have a fairly significant capacitance (...
by Jeroen
Fri Jul 17, 2020 12:33 pm
Forum: NES Hardware and Flash Equipment
Topic: CPU clock madness
Replies: 4
Views: 933

Re: CPU clock madness

Whilst I don't know what causes the discrepancy. I can tell you that your assumption that the oscilloscope probe shouldn't affect the crystal isn't necessarily true. Yes, it has a high input impedance...however it also has a load capacitance. Crystal circuits are a bit atypical in that small parasit...
by Jeroen
Fri Jul 17, 2020 11:03 am
Forum: NES Hardware and Flash Equipment
Topic: Standardizing symbols for PCB mirroring pads
Replies: 34
Views: 5129

Re: Standardizing symbols for PCB mirroring pads

Although I like the checkerboard symbols. I have to wonder if they'll be very legible on boards produced by some of the cheaper PCB houses. (Obviously if you make it big enough any board house will be able to do it, but I mean at smaller sizes)
by Jeroen
Fri Dec 28, 2018 4:00 pm
Forum: NES Hardware and Flash Equipment
Topic: NES Low-Pass Filter?
Replies: 20
Views: 12240

Re: NES Low-Pass Filter?

Right, but the nes doesnt natively output S-video, so you wouldn't actually get any improvements over composite if you used a converter. That being said, composite -> s-video convertors often have something called a "comb filter", something which your tv might lack, which takes out some of the noise...
by Jeroen
Sat Dec 08, 2018 3:39 pm
Forum: NESdev
Topic: Castkevania problem with Famicom AV
Replies: 8
Views: 4626

Re: Castkevania problem with Famicom AV

Certainly strange that it would work with an everdrive...But I'm fairly confident the NESRGB mod is causing the issue here.
by Jeroen
Sat Dec 08, 2018 3:10 pm
Forum: NESdev
Topic: Castkevania problem with Famicom AV
Replies: 8
Views: 4626

Re: Castkevania problem with Famicom AV

Mmm the only thing I can think of that could cause the game to slow down is if the NMI line is intermittent, the game logic won't update at 60hz but at whatever rate is coming through on the pin. (could even be random noise!) Overall you might want to reseat the connections, since the palette is als...
by Jeroen
Sat Dec 08, 2018 2:33 pm
Forum: NESdev
Topic: Castkevania problem with Famicom AV
Replies: 8
Views: 4626

Re: Castkevania problem with Famicom AV

Ya I saw that right after I posted, see my edit above for more questions.