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Posts posted by MarkO

  1. Hi airsoftmodels:


    I'm a long time Apple ][ and Commodore C64 user, and I am still fairly new to the Color Computer...  I got my first one in the Fall of 2012...


    All the the above links are a great starting point, plus I would recommend, http://imacoconut.com/, as an aggregator to all the above links plus a few others..  Like Emulators and other Hardware Vendors..



    Just to give a bit of background, the Tandy CoCo is built on the Motorola 6809, ( MC6809 ), and has a BASIC that was developed by Micro-Soft, and is quite similar to the 6502 BASIC found in the Commodore C64 and Apple ]['s APPLESOFT.  In fact the the Hidden Easter Egg is still located in the ROMs  :



    Also, if you don't mind De-Soldering your CPU, there is an Upgraded CPU from Hitachi, called the 6309, ( HD6309 ), that runs identically in Emulation Mode, and when switched to Native Mode will run your code faster, at the same Clock Speeds:






    I "hang out" on the TRS-80 Discord Server, quite a bit, so if you want to ask a lot of question, of me or some other CoCoNuts, come join us......



    ( Disclaimer:  I'm an Admin on the TRS-80 Discord Server, so I'm probable biased... )



  2. Sorry Mark, it's not really stack blasting on the 65816, as it can't load multiple registers from a single instruction like the 6809 or 6309.

    You can certainly use the stack pointer as a data source but it's much less efficient. It's really no better than doing the same thing on a 6803.


    << SNIP >>

    The 65816 can has a Stack a big as 64K, and As I Recall, using two Stack Pointers, you can ( relatively ) move Data from One Area of Memory to the Screen Buffer much quicker that with Loading and Storing the Accumulator.




  3. With the implementation of flow control, I've cut an alpha release of PLATOTerm, it's here:




    It does not have character set loading yet, so some things will still look a bit weird.


    It is HIGHLY recommended that you enable hardware handshaking (e.g. &K1 &P0) to improve reliability.


    More to come!



    Looking really good, Tom!!!!!



  4. I am an Old Apple ][ guy ( and Commodore SX-64 Guy ), but I have only got into the CoCo's 6 years ago...



    I got a CoCo 3, NIB with an Apple //e Platinum.. I thought about selling it, but the MC6809 was too cool to not try out.. ( If you find the MC6809 cool, wait until you find out about the HD6309.. )


    Since that point, I have added a CoCo 2, another CoCo 2 with a CoCo 1, and another CoCo 2.. Two MPIs, Two CoCoSDCs, Two CoCoPSGs, and Two CoCoGMCs... And a couple FD-500s..



    The MC6809 is a way more Capable CPU than the 65xx, even at .89Mhz, and the CoCo 3 you can Double that, and if you swap in the HD6309, you will move it up another notch in performance..


    The CoCos have a 6 Bit DAC, that can make pretty nice sounding music, but it is very CPU Intensive... No Sprites, but the Stack Blast trick that can be done on the 65816 can be done on the MC6809/HD6309.. The Nuclear Green Screen is very Off Putting, but I think that was to keep the Casual Users away....



  5. << SNIP >>


    The Cartridge Games are written in Assembly Language, so the BASIC is not relevant...


    I just found out today on CoCoTALK! Episode #63, that initially the CoCo's Cartridges were not to rely on any of the ROMs in the CoCo, but later were allowed to access "certian" routines ( Functions )... Per Steve Bjork and then Mark Siegel both who wrote Cartridge Games for the CoCo, BITD...







  6. Thank you. From that list I see nothing from the cartridges standpoint that would

    make a difference for a CoCo 1 or 2, agree?



    It has been discussed in the CoCo Areas, "Can Software detect the difference between a CoCo 1 and a CoCo 2?"


    Other than finding 4K of RAM, ( CoCo 1s Only ) or Standard BASIC v1.0, ( I am fairly sure that Standard BASIC was v1.1 by the time the CoCo 2 was shipping ), there doesn't seem to be a way to tell a CoCo 1 with 16K and Extended BASIC or a CoCo 1 with 64K and Extended BASIC and a CoCo 2 with the same RAM and BASIC..


    My CoCo 1 happens to have 64K from a period mod that upgraded it.

    Therefore, it has one of the extended color basic versions too to be able

    to use the extra memory. So mine is probably closer to a CoCo 2 than

    many but I don't even think that necessarily matters.

    Your CoCo 1 might have been upgraded to 64K, but the BASIC might not have been... Extended BASIC needs 16K at least, but Standard BASIC doesn't care...


    The Cartridge Games are written in Assembly Language, so the BASIC is not relevant...



  7. << SNIP >>


    Sorry I'm a relative CoCo noob here...

    What would keep this from working in a CoCo1?

    (or 3 for that matter?)

    I am fairly new to CoCos too..


    Electronically there isn't much difference between the Coco 1 and CoCo 2.. CoCo 3s have a lot of differences...


    The CoCo 1 has a 12VDC Supply plus the 5VDC... The CoCo 2 and 3 only have the 5VDC.


    The CoCo 1 came with Standard BASIC and if it had 16K or 32K ( and Later 64K ) it could have Extended BASIC.

    ( CoCo 1s were 4K or 16K and later were expandable to 32K, and once the White CoCo 1s came out they were 64K )

    The CoCo 2 came with Standard BASIC and it could have Extended BASIC.

    ( CoCo 2s were 16K or 64K )


    The early CoCo 1s had the Chiclet Keyboards.. The later 64K CoCo 1s came with the Lower Profile, ( meltey key ) Keyboards that the early CoCo 2s came with .


    The CoCo 2s were Cost Reduced, in that the Circuit Board was Smaller, so more CoCo 2 Motherboards can be made from the same size Sheet.


    I googled around for what would make a cartridge CoCo2 specific and got little except

    maybe differences in the Basic ROM and CoCo 2s shipped with more memory....

    Maybe and Maybe


    See Techno's Page for the Models and their Configurations..




    • Like 1

  8. I have an SX-64 as well as a couple C64's with the 1541's.. And a C128 with a C1571... I am trying to locate my RS-232 Cart.. :(


    I have some ESP8266 devices that will connect up to the RS-232 Cart, once I find it...



    I don't have a NIC for the C64 yet, but planning on getting one...


    I have some version of the Super CPU for the C64, but I have not tested it yet...



  9. Dave Phillipson ( programmer of an OS9 Level 2 program called Supercomm ) said:


    "Tell him the unravelled book has got it. He’s also got the start address wrong. It is $C000 not $C800. I just checked "DISK BASIC UNRAVELLED II" and it’s right there on page B2. The DIsk ROM is the same regardless of which model of CoCo."







  10. I am working on a melted key CoCo 2. I changed the stock ram chips to 4164 chips fresh from Jameco. I jumpered the solder pads on either side of the w1 silkscreen.


    ?mem only shows 8k. I tried a second set of 4164s with the same result. Should I bother with a 3rd set of ram chips or might this be some other component causing the issue?


    That is Strange... I did the same update, in the same manner on a friends Melted Key CoCo 2 and it worked fine...


    I would check all the Sockets and Pins looking for a Poor Connection.. If the Upper Address Lines were In-Op, the computer could not access the Upper RAM...




  11. OK here's the last 2 images I'll be uploading for this. Time for me to move on. Hopefully this will provide what you need.

    Thanks for the Pictures.. If one of these needs to be built, we have the Circuit and Components....




  12. Thanks, yes, I've tossed it. Not going to waste any more time on it now that I know it's nothing crucial ;)

    It would have been interesting to know how it worked...


    Since there are Four Paddle Ports, that look for a Variable Resistors between 0 Ohms and 150K Ohms, you could make "a key" by using Four Resistors of the same or different values, and have your program read the values and determine if it's the Right Dongle...



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