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Kroko

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Posts posted by Kroko

  1. Posted

    Has anyone else done this, and encountered (and solved) a similar problem?Thanks

    How are you dumping the chip ? are you using an edge connector and plug the cart in, or are you directly reading from the chip ?

     

    When I first looked at a PacMan rom chip, i found that the pin assignment on the pacman rom is NOT identical to a 2732 EPROM.

     

    The wiring on the PCB is such, that the right lines come out at the edge connector, but you can't treat the chip as if it was an EPROM. Here is the Pin assignment for a PacMan ROM:

     

    Pin 1 to 17: same as 2732 EPROM

    Pin 18: A11

    Pin 19: A10

    Pin 20: CE (A12)

    Pin 21: OE (bridged to VCC)

    Pin 22: A9

    Pin 23: A8

    Pin 24: VCC

     

    You should use the edge connector to dump ROMs, not the chip. Custom ROMs may have any Pin assignment.

     

    If you are already using the cart connector, can you please explain a bit better which problems you have. What do you read ? From a different location or rubbish ? You can easily compare what you read with existing ROM dumps.

  4. Posted

    Before you say flash rom is not a good choice: What is better than flash memory :?:

     

    pure RAM: game lost after power down.

     

    timekeeper/zeropower RAM: very large package size, very expensive and I could not get a device larger than 32K. Will only be able to hold its data for a few years, then fail.

     

    MRAM: not available for krokodiles, yet :(

     

    Memory cards together with menu system and RAM: Better, but would have made the design much more complicated and expensive.

     

    parallel EEPROM: far too expensive in 512K size.

     

    So there were 2 possible ways to go: memory card or flash-rom.

    I chose flash ROM, because:

    * less expensive

    * can be produced at home (so I can make more any time)

    * cart can exactly behave like the original cart (instant on)

     

    disadvantage: If you are unlucky, you may have to pay 5$ for every additional 10000 writes to the cart.

     

    A question of taste, if you ask me :)

  6. Posted

    Texas Instruments UA7805 for example has 25V. It definitely depends on the manufacturer  :)

     

    http://focus.ti.com/lit/ds/symlink/ua7805.pdf No it doesn't, atleast not anymore... :wink:

     

    However; I have found a 7812 datasheet in my stuff from 1976 that quotes 20V max so it definitely matters how old the device is, and the manufacturer.

     

    I am usually careful about differences between newer and older RF transistors, but I usually ignore really common stuff and ICs thinking they are all the same, I guess I know better now.

     

    Ah I think I got it now ! You were looking at page 2 of the datasheet. The absolute maximum rating is 35V. I was using the recommended operating range on page 3, and that is up to 25 V. I don't think it would be a good idea to use a 35V power supply. I am a coward, you know ... :D

  7. Posted

    The Krokodile Cart does not do anything before startup. It starts as if it was the original ROM. So the state of all VCS registers and RAM will not be changed.

    Except when you use the menu, right?

    Yes, in a multicart, the RAM is cleared and the game starts from bank 0. Each ROM of type 4K,F8,F6 and F4 can be patched such, that RAM is cleared and that it is started from a fixed bank. When it is patched, the ROM is a multicart with only one game which is selected immediately.

  8. Posted

    My guess is that the flash in the KK is good for 100,000 writes.

    Yes, thats also what I think. The 10000 is the absolute minimum that is guaranteed, but in reality they survive much longer. Even for the developer, who may download quite often (Thomas!) we have invented this incremental download feature, which will only change parts that really need to be changed. This is also a good way to make it survive longer :D

  9. Posted

    ALL chips on the Krokodile Cart are socketed. The flash chip, the chip for the serial communication and RAM can be replaced by anybody. The controller and the logic chip can only be replaced by me, because they have to be programmed ...

     

    The Krokodile Cart does not do anything before startup. It starts as if it was the original ROM. So the state of all VCS registers and RAM will not be changed.

  10. Posted

    However, I always remember the max input for any 78XX series regulator was always 35V (as far back as I can remember) max, and a newer (less 5 years old) data sheet

    Texas Instruments UA7805 for example has 25V. It definitely depends on the manufacturer :)

  11. Posted

    What should this measure when measuring voltage and amps?

     

    The Atari needs 5V for its chips and other circuitry. So it is using a device that is called voltage regulator, that can make 5V out of any voltage that is higher than 5V. The ideal input voltage for the consoles regulator is 9V and that is what the original power supplies have.

     

    There is also a maximum voltage such a voltage regulator can handle at its input. If there is more voltage, it will be destroyed. In general the higher the input voltage is, the warmer the regulator gets until it is destroyed. Different regulators can handle different maximum input voltages. Modern 7805 have a maximum input voltage of 25V. (But i would not rely on that for the old VCS regulator)

     

    :arrow: use 9V and you are fine !

     

    Now to the current. The current in Amps or milliamps just tells you, how much current the supply CAN supply. So the higher this value is, the better.

     

    In theory you cann directly connect an atomic plant with 100 Terra Ampere to your vcs, as long as it produces exactly 9V. The power that is drawn from it will never be higher than the maximum rating of the voltage regulator. If it can supply 1A, there is no way to draw a lot more from your power supply (Some power is lost at the voltage conversion process)

     

    6 switch supplies have 400mA, the juniors have 500mA rating. So If you buy a supply, don't buy one that has less than 500mA. If it has more, it will work as good as the 500mA supply, but it will be more expensive :D

  12. Posted

    I've got one on order and would really like to use it with my iMac G5.   Any word on the Java app?  If not, are the program specs available so I could write a Native Mac app for it?

    I hope Andrew Davie will make a Java Commander in the future. But it is not available yet and I am not sure if Andrew has enough time to write it in the near future.

    If you want to make your own Java Commander, I will be happy to send all necessary information to you. Just send a PM with your e-mail :)

  13. Posted

    Will I be able to order one of these awesome carts in a month from now?  More likely end of February or early March?

     

    Yes, you will be able to order the device later. I do not plan to stop production unless there is a good reason. But it will no longer be possible to preorder them. You can just order them in the AtriAge store if they are available. Maybe it will take a while until I can make more devices than those that were already preordered, but I definitely will make more.

  14. Posted

    The cable is easy to build, but I've had a very difficult time getting Star Commander working.  Hopefully 64HDD is better.  

     

    Somebody needs to build a similar USB device that has hardware to handle the timing issues associated with the C64's serial port.

     

    -paul

     

    I have made a prototype of such a device. But I don't think its worth the effort. cbm4win will do the job in the future. And there is cbm4linux ...

    If you want to have a look at the prototype:

     

    http://www.bitcity.de/1541%20Serial%20Interface.htm

     

    I would just have to replace the max232 with and USB chip and the serial connector with a usb connector ...

  15. Posted

    I personaly don't understand the need for a pitfall chip.  It can be emulated just fine. Why can't that emulation be made into emulation-on-a-chip like a Pic or Microcontroller, or even if it needs to be an entire daughterboard with a more readily avaialble sound generator and interface. Legality issues aside, I'm sure it could be physicaly done.  :ponder:

    Is there a technical description available anywhere ? All I know is, that there is a cool sound chip on Pitfall II. But are there any specifications available where one could see what it does (exactly) ?

  18. Posted

    As for 3E support. I think the most natural method would be to have pages 0 - 119 be the ROM. Rather than pages 8-127. It sounds like the KK would handle this arrangement without modification. (I'm assuming that it copies the last 2K of a ROM to the last 2K of the 512K address space for both 3E and 3F.)  

     

    On the Krokodile Cart ROM and RAM are different chips. So to be compatible, the mode must be such, that writing

     

    0-31 to location $003E selects RAM Bank 0 to 31 (no matter were it physically is on your RAM chip) These banks have a size of 1K.

    0-239 to location $003F selects ROM Bank 0 to 239 (whereever it may be in your RAM chip) These banks have a size of 2K

     

    This example is for an upper limit of 32K RAM (32RAM Banks)

    For 64K RAM it would look like this

    0-63 (RAM)

    0-223 (ROM)

     

    It is necessary that each banknumber starts at zero, because it is implemented that way. CURRENTLY the Ram banks are mirrored if you go upwards. So if you select RAM bank 32 you end in RAM bank 0 and so on.

    But we really should keep higher numbers for higher banks in the future if this mode is extended to say 64 K RAM ...

     

    Wouldn't it be possible to just activate a higher memory area of your RAM chip if a write to 3E takes place and enable CV access for that area ?

     

    I think we should try to agree on an upper limit for RAM so that you can decide from which point upward you want to map in your RAM banks. And you need to choose a starting adress from which it is easy to map the RAM banks ...

     

    I still think it makes sense to wait for the first project that is done with it and let Andrew decide how much RAM/ROM makes sense for that mode.

     

    I don't hink we get problems with the fixed bank. Just let everything as it is in 3F switching. The vectors are in the last 2k of the ROM. If we keep it such, then I don't expect problems. How your hardware is dealing with the fact, that the fixed 2K bank is always the last bank of the ROM is not so important. The KK does it by always using the physical bank 255 as the fixed bank. So if you use a smaller ROM the last 2K have to be copied to that location.

     

    I hope this was not too confusing :D

     

    Armin

  19. Posted

    It could do 3E-. (480K ROM, 32K RAM). So authors who wanted things to run on both would have to restrain themselves to using only the first 480K of ROM.

    Please don't forget that 3E could be expanded in the future such that we have 256K of additional RAM available. The only reason why there are currently only 32 is the size of my RAM chip. but the concept is such that you can have 256 ROM banks and 256 RAM banks.

     

    My suggestion is, we wait until "something" is available for 3E and then agree on how 3E should be expanded in the future. Can't think of any application that could really need 256K RAM :ponder:

     

    But before you make a 3E version for the CC2, we should ask people how much RAM they COULD want to use in the future to find the best compromise between ROM and RAM size.

  20. Posted

    I assume since this is in part a commercial for the Krokodile cart that no ROM would be forthcoming. (And note that I have no problem with that.)

     

    There are no secrets!

     

    512K 3F switching is like "normal" 3F switching. The only difference is, that the fixed bank is always at the highest 2K of the 512K ROM. Apart from that, just switch in the selected bank. The download software has to make sure to copy the highest 2K of each 3F ROM to the last 2K of the 512K adress space of the cart.

     

    3E is just an extension to 3F. If works exactly like 3F, the only difference is, that a write to 3E switches out the current ROM bank and switches in one of 32 RAM banks. RAM access works like with Commavid RAM. Read port is lower 1K and write port is upper 1K.

     

    So you get 512K Rom and 32K aditional RAM

  24. Posted

    What's the top amount of memory that can be added to a 2600 cartridge's RAM? I'm not talking about the game's ROM, I'm talking about the type of added memory that CBS's RAM Plus carts and the Starpath Supercharger had.

    In principle there is no limit. The only challenge is to define a good way to access it from your code ...

     

    I've read that a large amount of extra memory on a cartridge will draw too much power out of the console, and short it out. So, has anyone found what the top limit of added cartridge memory is?

    I don't hink that this is true. The amount of power that is drawn from the console is not depending on the RAM size, but on the power consumtion of the used chip(s). If the RAM chip is active, the ROM chip is in standby and consumes less power. Todays RAMs do not draw a lot of power ....

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