Need help reading a schematic.

[stj]

Re: Need help reading a schematic.

to do the moving dot thing is easy,
set a couple of variables in memory for X & Y
write a character to (videoram+X+(Y x line-length))
start a loop
read the keyboard interface
if it wasnt a cursor key, loop
overwrite the character in (videoram+X+(Y x line-length))
add / subtract from X or Y
write the character in (videoram+X+(Y x line-length))
loop

obviously a delay in the loop or it will be running in mega-turbo speed!

[stj]

Re: Need help reading a schematic.

obviously you would do some boundary checking on X and Y values so you cant go off-screen.

[Spork Schivago]

Re: Need help reading a schematic.

to do the moving dot thing is easy,
set a couple of variables in memory for X & Y
write a character to (videoram+X+(Y x line-length))
start a loop
read the keyboard interface
if it wasnt a cursor key, loop
overwrite the character in (videoram+X+(Y x line-length))
add / subtract from X or Y
write the character in (videoram+X+(Y x line-length))
loop

obviously a delay in the loop or it will be running in mega-turbo speed!

Yes, I understand the pseudo code all right. I can write it in C for the PC just fine. My trouble was with the assembly part of it and the whole CHR-ROM / CHR-RAM stuff. The assembly tutorials I found for the 2A03 weren't very complete. I think maybe they're designed for someone who already knows assembly for the 6502. Mainly, I was following the wiki located here:

http://wiki.nesdev.com/w/index.php/Programming_guide

If you look at the Programming Basics section, you'll notice a lot of To be writtens...

[stj]

Re: Need help reading a schematic.

first and most crucial thing to writing in assembly or hex is a full and accurate memory-map.
because you arent going to be referencing or linking someone elses library's!

none of that stdin crap etc.

[Spork Schivago]

Re: Need help reading a schematic.

first and most crucial thing to writing in assembly or hex is a full and accurate memory-map.
because you arent going to be referencing or linking someone elses library's!

none of that stdin crap etc.

Okay. That makes sense. Learning the instruction set would be the second most crucial thing to writing in assembly?

[stj]

Re: Need help reading a schematic.

yes, very easy on 6502, one accumulator, 2 index registers, both 8bit.
only about 50 instructions - half of them you wont use.

just remember that the stack is in low ram - dont write into it!!

[stj]

Re: Need help reading a schematic.

http://6502.org/

[keeney123]

Re: Need help reading a schematic.

Technically, I think the CPU the NES uses is a Ricoh 2A03. I believe it's just a modified version of the MOS 6502.

Originally, MOS developed it then Commadore bought it and sourced it to Rockwell and Synertek. After that though, a few other companies got access to it. I don't know who though. Chuck Peddle's team at MOS developed it.

Thanks for that info. I came across this Processor in a plug-in board that an Apple computer used in 1986. I believe at the time the board and the software was consider the driver.

[Spork Schivago]

Re: Need help reading a schematic.

Thanks for that info. I came across this Processor in a plug-in board that an Apple computer used in 1986. I believe at the time the board and the software was consider the driver.

Here's a little more info. This is what Wikipedia has to say about the 2A03...

Ricoh 2A03
The Ricoh 2A03 or RP2A03 (NTSC version) / Ricoh 2A07 or RP2A07 (PAL version) is the 8-bit microprocessor in the Nintendo Entertainment System video game console manufactured by Ricoh. It contained a second source MOS Technology 6502 core, lacking the 6502's binary-coded decimal mode, with 22 memory-mapped I/O registers that controlled an APU, rudimentary DMA, and game controller polling.[1] It was also used as a sound chip and secondary CPU by Nintendo's arcade game Punch-Out!!

Regional variations
European and Australian versions of the NES used the Ricoh 2A07 or RP2A07 processor, which was identical to the 2A03 except for a different clock divider and the 50 Hz vertical refresh rate used in the PAL television standard.

[stj]

Re: Need help reading a schematic.

it's actually used in the nintendo VS arcade system - never trust wakypedia.

[Spork Schivago]

Re: Need help reading a schematic.

it's actually used in the nintendo VS arcade system - never trust wakypedia.

Stj, I agree that wikipedia isn't the best source for information. I always try to verify by looking at the source. I think the reason they listed the Punch Out Arcade is because it's special. I believe what they're talking about is that it actually had 2 single channel amps to produce different sounds from the left and right speaker. They used the Ricoh 2A03 for that setup I believe. I believe it had the Zilog Z80 for the main CPU. The 2A03 was just for sound I think. Might be wrong there though, having trouble finding the info on the technical specs.

Can you confirm my information on the Punch-Out arcade?

[stj]

Re: Need help reading a schematic.

http://www.mamedev.com/downloader.ph.../mame0167s.zip

that has everything you could ask for.

[Spork Schivago]

Re: Need help reading a schematic.

Thanks. I've seen custom built arcade machines that run off of MAME. I always wanted to own an original coin-operated arcade. One where the coin slot still worked. They're always a bit too expensive though, at least the good ones. I wouldn't mind something like Ikari Warriors or some fighting game. At a local comic book, they had a broken arcade, it was four player. It was X-Men I believe and looked like this: http://cdn.pastemagazine.com/www/blo...n%20arcade.jpg

I asked the guy if he'd sell it, he said it wasn't his. It was his buddy's and he was just storing it there. I asked if he could ask his buddy if he wanted to sell it and he said other people have asked him and it's always a no. I thought a broken one might not of been that hard to fix, if it was the circuit board, and I might of gotten it fairly cheap. I don't really want one running an emulator or anything. I'd like an original, used in the arcade, type of machines. Also, I'd love to get a pinball machine some time.

[stj]

Re: Need help reading a schematic.

keep your eyes on ebay, loads of arcade machines there.
i'm not a fan of mame arcade cabs, they arent acurate.

[Spork Schivago]

Re: Need help reading a schematic.

keep your eyes on ebay, loads of arcade machines there.
i'm not a fan of mame arcade cabs, they arent acurate.

Agreed. I check e-Bay once in awhile but the good ones are over a grand usually! I saw some TV show, maybe a pawn shop one or a restoration one, and they were selling a guy a Ms. PacMan arcade machine. He came to look at it, to give the guys lots of money, then he realized the cab wasn't even painted. They just used decals for it. I'd be afraid of something like that happening to me.

Craigslist has some for like 400$ once in awhile. Might try to pick one up there. There's another machine I've been looking for for years but I can't find the right one. It's a coin pusher / shooter. You use quarters and when you put one in, the quarter goes down on a table. There's a bar that pushes the quarters and when your quarter goes down, if the pusher bar pushes any quarters off, you get to keep the quarters. The one I want has an arm where you put the quarter though. You move the little bar that the quarter rolls down, to where ever you want, and put the quarter in when you're ready (or maybe you put the quarter in, move it around and then pull a trigger when you're ready). The arm that you move is by your waist. I played one like that a few times when I was younger but can only find the newer models. Boy would I love one of those things.

[stj]

Re: Need help reading a schematic.

pushers are large beasts - and they are rigged.

if you look real close, there is a tiny lip on the edge of the bed so the coins get pushed to the side as they hit the edge.

now if you look over the edge, you will see that coins that drop at the outer-edges of the shelf go to the cashbox, not the collection tray.

if you really want one, keep an eye on fairgrounds and such, they go real cheap when these places upgrade.

[Spork Schivago]

Re: Need help reading a schematic.

pushers are large beasts - and they are rigged.

if you look real close, there is a tiny lip on the edge of the bed so the coins get pushed to the side as they hit the edge.

now if you look over the edge, you will see that coins that drop at the outer-edges of the shelf go to the cashbox, not the collection tray.

if you really want one, keep an eye on fairgrounds and such, they go real cheap when these places upgrade.

<Gasp> I didn't realize they were rigged! Man, I spent so much money on that game when I was kid. Only played it twice or so, at some fair ground, but I spent like 25$ each time on it in quarters. Maybe I should try to make one some time, one that isn't so rigged, just to give people a better chance of winning. I'd mostly have it just for fun.

[stj]

Re: Need help reading a schematic.

everything in fairgrounds is "regulated" in one way or another.
if you think that's bad, you should see how the cranes work!!!
i'll give you a hint - they are intelligent and can regulate the chance of winning.
some even network to a remote terminal in groups!

[Spork Schivago]

Re: Need help reading a schematic.

everything in fairgrounds is "regulated" in one way or another.
if you think that's bad, you should see how the cranes work!!!
i'll give you a hint - they are intelligent and can regulate the chance of winning.
some even network to a remote terminal in groups!

The crane we have around here, down at Wegmans is pretty decent. My wife wins just about every time she plays. She always tries giving the stuffed animals to near by children. I see one machine when I lived a good 100 miles away though, they freaking loosened the screws so it wouldn't grab properly. They got this game called Barber Cut or something like that, that's rigged. Light House is another rigged one.

[stj]

Re: Need help reading a schematic.

it's not screws.
the grabber uses an electromagnet, the control system regulates win's by varying the current to the magnet.

early systems just had a "power" control.
newer ones monitor wins over time and make it harder as people win, and make it easier over time when people dont win.

the idea is that if people never see a win they wont play, but at the same time you dont want it being emptied.