Vigo

Here you go again: https://www.filehosting.org/file/details/807882/Max10_SD_fixed_bus_contention.zip Actually, I am wondering why this hasn't already made it into the official firmware update, since the problem I have described should be quite apparent for anyone, who can read the original Atari 800 schematics: http://www.jsobola.atari8.info/dereatari/literatdere/400_800sm.pdf Page 64. S4 and S5 on J108 & J109 are ALWAYS selected by the 74LS42 (Z101). The OR gate (Z102) is only masking the signals for the RAM cartridges. This fix is basically a no-brainer. But right now, without fixing this issue, the Ultimate Cart should not be used in an original Atari 800. Best regards, Vigo

37899, and not 37902? Whether the 6502 can still write properly to the affected memory area depends on the value the FPGA places on the data bus during bus contention. Each "1" bit coming from the FPGA can be pulled down to "0" by the NMOS 6502. However, a "0" bit will most likely stay "0", no matter what the 6502 places on the bus. Fact is that the Ultimate Cartridge relies on a XL/XE MMU behavior which the original 800 design does not provide. This can be easily verified by checking the Atari 800 schematics - the /S4, /S5 outputs from the 74LS42 do NOT get disabled by RD4 or RD5, they are ALWAYS active. But the current FPGA firmware always drives the data bus when either /S4 or /S5 is pulled low. So, no matter if it has worked "by accident" for you, this is an issue which needs to be fixed. Maybe you get those last 3 bytes back by trying my firmware code: https://ufile.io/34bi949t

Hi there, so, it turned out that my Ultimate Card had a weak solder connection on the TMS pin... Anyway, I resoldered the pin, reprogrammed the FPGA, and now my Atari 800 reports 37902 bytes from Basic (as it is supposed to do)! Therefore, I consider that the fix I proposed here in this thread is working correctly. Strange that I seem to be the first person to notice this issue...

Hi Robin, thanks for recognizing the issue. I actually compiled a new FPGA bitstream now, but I'm struggling to get the FPGA updated with my original (expensive) USB Blaster Rev C (Error 35).... The correct VHDL line, btw, is: CART_DATA <= data_out when ((CART_S5 = '0' and high_bank_enabled = '1') or (CART_S4 = '0' and low_bank_enabled = '1') or (CART_CTL = '0' and (sic_read_d500 or xex_read_d500))) else "ZZZZZZZZ"; Any Atari 800 user can easily confirm the issue by starting any Atari BASIC revision and typing "PRINT FRE(0)" <RETURN>. An 48K machine will only display "29710" (=32K memory detected). This is because the FPGA is driving the data bus, even though RD4 has been correctly set to low (RAM enabled). Now gotta fix this stupid Programmer issue I have....

Hello together, I have found a compatibility problem with the Ultimate Cart and the classic Atari 800 (non-XL/XE) computer. When using the Ultimate Cart on this machine, any memory access to non-enabled ROM area will nevertheless cause a bus contention with the underlying RAM at $8000-$bfff. The reason being that the Ultimate Cart relies on the Atari XL/XE MMU behavior that /S4,/S5 is disabled when RD4,RD5 is kept low. But unfortunately, on the Atari 800, /S4 & /S5 are always active. Only the RAM is not mapped when RD4, RD5 is driven high... The problematic part of the FPGA code is here: CART_DATA <= data_out when (CART_S5 = '0' or CART_S4 = '0' or (CART_CTL = '0' and (sic_read_d500 or xex_read_d500))) else "ZZZZZZZZ"; FPGA always drives data bus drivers when /S4 or /S5 is pulled low. It should mask the read data according to the state of RD4 & RD5: CART_DATA <= data_out when ((CART_S5 = '0' and CART_RD5 = '1') or (CART_S4 = '0' and CART_RD4 = '1') or (CART_CTL = '0' and (sic_read_d500 or xex_read_d500))) else "ZZZZZZZZ"; Since this is an easy modification to gain full compatibility, I would strongly recommend to include it in the official firmware branch. Otherwise, people as myself will experience strange glitches and instabilities when using 8K ROMS on their Atari 800 (e.g. doing as simple things as just loading the BASIC cartridge). Thanks!

Don't know how I forgot that one. Too bad Bally didn't chose to distribute the Home Library Computer/Arcade more widely. Otherwise I think it would have been much more of a contender. Seems that it comes with an integrated pocket calculator!

Perhaps it just boils down to what we grew up with. Still, I'd really like to know why they changed it. Especially the grey/light purple colour scheme is so... weird. Almost like a medic instrument. No wonder the Sega Genesis gave the SNES a hard time in the US...

I have never read any explanation why Nintendo changed the SNES design for the US market. I remember back as a kid, I always wondered why the SNES depicted in the manual of US imported games looked so different and clumsy.

What do you think speaks against this? That the grandfather did most probably not intend to kill his grandson? This obviously wouldn't have been abuse, but murder. From my standpoint, carelessly bringing a child in a life threatening situation and obviously going against your duties as an adult towards minorities, clearly fits the definition of abuse. "Sometimes, people make mistakes" is IMHO a weak excuse, because OBVIOUSLY people worldwide make mistakes, not only sometimes, but on a daily basis, causing lots of pain and suffering. Everything, which I pointed out happening in this video in my previous posts, is INEXCUSABLE. "My grandson died! Well, sh/t happens. At least I can plug in my game now again..." I am stopping to discuss this topic now, because I already said what I wanted to say, and any further arguing would , at best, be going around in circles and at worst, end up me getting really angry.

Which to me shows that he actually had an idea that this was a dangerous situation. In this case, you don't tell your grandson to stay on his feet, but to STAY OFF. You call the fact that the kid was being electrocuted THREE TIMES, while grandpa was chuckling, not horrible? Have you seen how the kid hold his arm in pain at the end? It would have been his first duty to bring the kid to an hospital IMMEDIATELY instead of laughing his *ss off! Electric shocks can cause cardiac fibrillation hours after the exposure happened. It also can temporarily change the chemistry of your body, causing a shock. For me, this case is crystal clear. And I seriously don't understand people remotely defending this guy. This video documents the most irresponsible treatment of a child by an adult I have ever seen!

If you need proof, just watch the video. For the reasons I mentioned in my previous post. This kid is only alive by sheer luck. His grandpa endangered his life several times, and did NOTHING to help him. He even laughed at the whole situation.

http://en.wikipedia.org/wiki/Child_abuse Child abuse is not only about child pornography, as most people seem to think. It is also about acting irresponsible by exposing your child to dangerous situations. In this case here, the immediate danger of death by electrocution. If this kid would have died or being treated in hospital due to serious injuries, grandpa would be in a lot of trouble now... No matter if he intended harm or not. As an adult, YOU are responsible for the well-being of minors. YOU have the responsibility to KEEP YOUR KIDS AWAY from the dangers of electricity, especially high voltages. And this whole video shows an unacceptable lack of care and responsibility. That he did NOT unplug the game while his grandson was touching the backplate of the electron gun with his bare hands is INEXCUSABLE. That he did not give his grandson at least some SAFETY GLOVES is INEXCUSABLE. That he talked his grandson into removing the high voltage cable from the anode of the tube, without grounding it first, and again with his bare hands, is INEXCUSABLE. That he watched and even CHUCKLED about his grandson being electrocuted THREE TIMES, without taking IMMEDIATE ACTION by bringing this kid to a hospital is INEXCUSABLE. What I absolutely don't understand is, there are morons here who are actually DEFENDING this behaviour!

Yeah, let your kids play with high voltage, it's alright. Here, bite into the the red one, Grandpa is even filming you being roasted. And yet, you seem to approve of all this. Since it is general knowledge that electricity never needs to be feared... Come on, join hands, it's your friend, son! What??? If you don't know what you are doing (and that is apparently the case in this video), you are not only useless, but also a danger to yourself and other people. Especially if you are an adult and guiding minorities who trust you, and for who you are responsible! So I AM being a sad soul because I am RIGHTFULLY HORRIFIED that this guy let his grandson handle HIGH VOLTAGES with his BARE HANDS? That this idiot didn't even unplug the game? Being responsible for your grandchild's death because of your incompetence as an adult is a guarantee of becoming a sad soul.

This is a joke, right? This old fart made his grandson touching the HIGH VOLTAGE (10.000-20.000 Volts) electronics of a PLUGGED IN game with his BARE HANDS! Congratulations, your grandson just got 3 zaps in a row. Did you see how the kid held his arm at the end when they were giggling like idiots? And obviously, this guy never heard of static electricity still residing in the capacitors and the tube after the monitor is being plugged off. The "red one" being mentioned in the video is the high voltage cable leading to the anode! Touch the blank connection, and make friends with several thousands of volts of static electricity still in the tube, joining the "life and death" lottery. It is pure dumb unwashed luck that the kid survived this. And apparently, there are more suicide candidates walking around here.

I am absolutely speechless... No seriously! http://de.youtube.com/watch?v=kLEMn76ZjDc This guy should be arrested for child abuse. :x

The same rules apply when the Jaguar was first released: no software = no system.

Though I am a big Amiga fan, I must admit that I really dislike the looks of the CD32: It's a horrible "design" (if one can call that). I much prefer the HiFi look of the CDTV:

One of the best PSX games IMHO: KULA WORLD ! http://de.youtube.com/watch?v=N8Tga-FuZns I love powerful games based on simple game ideas. Plus, technically, it's also top notch, because it's always running at full frame rate.

The PS3 is way easier to use than the PS2. Seriously, ask PS2 developers! That doesn't stop it from being a huge pain in the ass. I think Sony's biggest problem was not necessarily that the PS2 wasn't a well thought out hardware (in fact, it is very efficient), but that it differed A LOT from how PC's were built at that time. The key element to unleash the power of the PS2 is in using the 2 vector units, which I think heavily inspired the concept of vertex shaders found in modern GPU's. This presentation here explains it quite good: http://www.technology.scee.net/files/prese...programmers.pdf The first titles just used the R5900 for everything, including geometrical transformations, bypassing all extra features the PS2 provides. The only real drawback of the PS2 is the tiny amount of VRAM. But then again, since it is embedded INTO the GS, the PS2 had a killer fill-rate for its time, allowing lots of effects achieved through multi-passed rendering.

Hmm, from a design standpoint, both the PSX and Jaguar come from different school of thoughts. The Jaguar has a unified memory architecture and everything, being it program execution, data storage or graphics rendering, is using that bus (not taking the caches of the RISC into account). The PSX however, has strictly seperated buses for CPU and graphics rendering, and each side can only gain access to the other via DMA. So a Jaguar/PSX hybrid is something which would never ever make any sense at all. I think given the limited resources Atari had in the 90's, the Jaguar is a very impressive architecture. It easily beats anything produced before in video game business. The biggest mistake however is when the development tools are not good, which is especially fatal considering that the instruction set of the Jaguar RISC's are unique, so that no standard compiler could have been used. Perhaps they should have tried to license an already established RISC design (like MIPS), but then again, there is the money issue. 2 Co-existing platforms would have killed Atari even quicker than the Jaguar. And NEVER EVER consider ANYTHING Sega did right after the Genesis as a role model plan (except the Dreamcast, when it was too late)! Especially the 32X was an immensive flop. The problem is that Atari realistically could never have won the business back, no matter how hard they tried. Their financial resources were drained, the brand "Atari" had long lost its mass appeal, they had no killer apps to make the mass buy the console because of its software. The last point I think is the most important. If the game is great, you don't care anymore how much bits this system is supposed to have. The Jaguar, I am pretty sure, could have pulled off a decent port of Virtua Fighter for example. The problems is, games like these would have to be released right after the introduction of the Jaguar in 1993 to have a remote chance of surviving the rise of the PSX and Saturn. In my opinion, another mistake was the 64bit campaign. I don't want to start another bitness discussion here, since it is totally irrelevant to what I am trying to say now. What I am trying to say is: the games never reflected what the public associated with 64bit at the time. And I think that resulted in a huge loss of credibility for Atari. In all the talks about whether the Jaguar is 64bit or not, the fact that no game was able to convince people of this totally overshadowed the fact that up to this point, the Jaguar was quite a good design, much more capable than what had been released before.

Donkey Kong for the NES arcade perfect..... That's what she said...... But not what Shannon meant... Donkey Kong on the NES lacks 1 level, so it's by far not arcade perfect.

You can easily create games on the SMS which will look worse on both NES and 7800. The SN 76489 is nothing more than a 3 channel noise/square wave generator. Very boring stuff. It's a shame they did not put in the YM2419 FM chip in all SMS, not just the later japanese ones. Agreed. A 3.58 Mhz Z80 is outperformed by a 1.78Mhz 6502 in almost all cases.

Look, what are you trying to do here by warming up the same tiresome discussions over and over again? Your relativism doesn't make it any better. Obviously you somehow have gotten by now that the 7800 and the NES use VERY different methods of handling graphics. But that fact alone is no single way of comparing both machines. Nor indicating they achieve the same results with different methods. They are very different, and have advantages and disadvantages in almost the opposite kind of fields. That's why, again, it is more than stupid to keep this discussion alive if the 7800 could have done NES games equally well. No, it can't. It can do other types of games better, where lots of objects are moving in front of a simple background. "What if" discussions are pretty much irrelevant if they describe non-existing hardware. If you want the 7800 concept of displaying graphics pushed to the extreme, refer to the Atari Jaguar. Unlike the 7800, the Jaguar has enough horsepower to handle this kind of flexible grqaphics architecture efficiently. And obviously, you still haven't gotten the fact that displaying many (and huge) objects is NOT a weakness of the 7800. No amount of flicker will overcome the fact that the 7800 isn't able to display a fully tile based scrolling background with individual color attributes for each block. Yeah, of course let's make the whole screen flicker and enjoy seizures. I am repeating myself endless of times, and yet, I still have the feeling I could very well be talking to the kitchen oven with the same results... You make again and again and again the mistake of dreaming a dream where the 7800 is a NES. No, it is not. Want a banana?

It's the connection for the 4,43Mhz PAL colour crystal. Yes, the PAL TIA needs 2 clocks (3,55Mhz and 4,43Mhz) to function.

The problem is, we are talking about 66 TTL IC's in Pong vs. about 400 TTL IC's in Indy 800. Plus, in Indy 800, many parts of this game run at full 14.318Mhz speed (like car graphics rendering), while in Pong, the timing base for the whole game logic is 7.159Mhz (14.318Mhz/2). I don't say it is impossible, but this is more than a whole magnitude more complex than Pong. If I could get my hands on ROM dumps of those games, I would already have attempted to recreate more complex games like Tank or Indy 800 in an FPGA, so far the only method I can see to faithfully reproduce those games.