+tf_hh Posted June 24, 2017 Share Posted June 24, 2017 Hi, some weeks ago another ABBUC member ask me for a way to update his Atari 400 to 48K main memory. Until the end of 2016 mostly I prefer the usage of the genuine Atari 400 48K Factory Upgrade Kit - Atari part number CO61553. BEST Electronics offer them until somewhere up to the end of 2015 for approx. 25 USD each w/o any additional parts or manual. In 2016 the price rises up over 35 USD and now it´s sold out. Due to this impossible mission to get more of the CO61553, I create my own solution - even better than the original Here´s the Atari 400 48/52 KB RAM-Card with "external" OS-ROM support using standard EPROM sizes: This card is a full replacement for the 16 KB built-in RAM card. At least only two wires must be soldered at the bottom side of the Atari 400 mainboard. My RAM-card uses the same pinout like the CO61553 by Atari, but only 2 of the 4 wires suggested by Atari are really needed. But it works also, if you have already equipped an Atari 400 wit the CO61553, you can easily change to my RAM card, if you want. The 74LS243 chip has to be removed, it´s not needed any longer. After soldering the 2 (or 4) wires, just plug in the DIL connector into the socket were the 74LS243 was before, the other end has to plugged on the new RAM card. That´s all. The new RAM card uses SRAMs instead of DRAM and provides 48 KByte or 52 KByte main memory. When enabling the 52K RAM mode, the address range of $C000-$CFFF is also RAM. Please remind, that this area isn´t usable under BASIC (or, to be more precise, I didn´t know about that). A jumperfield on the PCB let´s you choose which size is active. The second new feature is the possibility of using a standard 27128 or 27256 EPROM for the operating system (and math-pack). When the "external" OS-ROM mode is enabled, the three ROMs on the Atari 400 mainboard won´t be used anymore. You can remove them or leave it in their sockets. The EPROM´s first 6 KB are unused, then 2 KB math-pack will be followed by the 8 KB OS-ROM code. A third jumperfield switches the highest address line A14 of the EPROM, so you can hold two different operating-system sets in one 27256 EPROM. What you get? - PCB "Atari 400 48K/52K RAM Card" with ENIG (Gold contacts) surface levelling. Picture shows only standard HASL, but I offer only the better quality with ENIG. - Ready-for-use crimped ribbon cable for the 74LS243 socket to connect with the RAM card - some wire for the 2 or 4 solder connections at the Atari 400 mainboard´s bottom - Installation instructions with pictures in english, sent by email Price? - from 20 up to 25 euros each depending on the amount of orders - Shipping costs to any place in the world for up to 5 pieces is 9 euros Schedule? - Please show your interest and how many you want to order here in this thread - I will collect inquires until 2017 July 2nd (end of date) - If 10 or more orders will be placed, everyone who´s interested get the payment details - Shipping out at the end of July 2017 Best regards, Jurgen 29 Quote Link to comment Share on other sites More sharing options...
+Larry Posted June 24, 2017 Share Posted June 24, 2017 That's just amazing! I don't have a 400, but still I can appreciate the neat product you've developed! -Larry 1 Quote Link to comment Share on other sites More sharing options...
beamer320i Posted June 24, 2017 Share Posted June 24, 2017 Absolutely superb Jurgen, please put me down for one unit! Quote Link to comment Share on other sites More sharing options...
olix Posted June 24, 2017 Share Posted June 24, 2017 I'm interested in one. Quote Link to comment Share on other sites More sharing options...
FULS Posted June 24, 2017 Share Posted June 24, 2017 Looks great!! I'll take two units. Quote Link to comment Share on other sites More sharing options...
SenorRossie Posted June 24, 2017 Share Posted June 24, 2017 The Super Color Card just arrived and already a companion for it presents itself. I am interested in one. Quote Link to comment Share on other sites More sharing options...
+Allan Posted June 24, 2017 Share Posted June 24, 2017 I'm up for one. Allan Quote Link to comment Share on other sites More sharing options...
+poobah Posted June 25, 2017 Share Posted June 25, 2017 I'd take one Quote Link to comment Share on other sites More sharing options...
venom4728a Posted June 25, 2017 Share Posted June 25, 2017 I would like 2 please. Quote Link to comment Share on other sites More sharing options...
+Stephen Posted June 25, 2017 Share Posted June 25, 2017 I'll take two. Quote Link to comment Share on other sites More sharing options...
Gandor Posted June 25, 2017 Share Posted June 25, 2017 I'm interested in one please Quote Link to comment Share on other sites More sharing options...
erichenneke Posted June 25, 2017 Share Posted June 25, 2017 this looks great... but i don't have a 400 ! (yet). Quote Link to comment Share on other sites More sharing options...
+David_P Posted June 25, 2017 Share Posted June 25, 2017 What is the other card in the second picture - the label "Pads for Incognito" certainly sounds intriguing... 1 Quote Link to comment Share on other sites More sharing options...
ACML Posted June 25, 2017 Share Posted June 25, 2017 (edited) Are you saying I can put any OS on the EPROM? Can I put the XL OS on the 27128? If yes, can I select between two OS's if I use a 27256? Was there a reason it couldn't go to 64K with the right OS? Edited June 25, 2017 by ACML Quote Link to comment Share on other sites More sharing options...
kazmat Posted June 25, 2017 Share Posted June 25, 2017 I'd take one Quote Link to comment Share on other sites More sharing options...
+tf_hh Posted June 25, 2017 Author Share Posted June 25, 2017 (edited) Are you saying I can put any OS on the EPROM? Can I put the XL OS on the 27128? If yes, can I select between two OS's if I use a 27256? Was there a reason it couldn't go to 64K with the right OS? No, any XL operating system won´t work without heavy patching. Main reason: The XL/XE OS assumes that PORTB is not used for joystick 3+4 input, it´s used for memory management. First no-go reason is the hardware test routine after power-up, which enables the Selftest part of the O.S. ROM ($5000-$57FF), jumps at a specific address and doing some memory checks. Without having memory cascade functions controlled by PORTB the OS will simply deadlock. This is the same reason why the RAM "under the OS" ($D800-$FFFF) isn´t usable without heavy mods in an Atari 400. At XL/XE systems bit 0 of the PORTB is used to switch between ROM or RAM in the area of $C000-$FFFF (except H/W area, $D000-$D7FF), without these functionality using the RAM under the OS won´t work. Yes, if using a 27256 type EPROM, you can put two OS on it. The jumper close to the left side of the EPROM is for selecting. You can use any "Oldrunner" OS or special patched versions like the Omnimon. When the RAM-mode of this new card is set to 52K, only 10 KB (2K math-pack and 8K OS) are mapped between $D800-$FFFF, the area $C000-CFFF is RAM. Using the standard-mode of 48K enables 14K ROM feature, then $C000-$CFFF is also ROM. Maybe some mods of the "personality card" (from Atari 800 system) may work then also in an Atari 400. I didn´t have such ROMs, so it´s not an "guaranteed feature", but technically it will work Jurgen Edited June 25, 2017 by tf_hh Quote Link to comment Share on other sites More sharing options...
+tf_hh Posted June 25, 2017 Author Share Posted June 25, 2017 What is the other card in the second picture - the label "Pads for Incognito" certainly sounds intriguing... This is one of my other projects. See http://atariage.com/forums/topic/260646-new-hardware-atari-400800-super-color-cpu-card/ for more information. Jurgen Quote Link to comment Share on other sites More sharing options...
ClausB Posted June 25, 2017 Share Posted June 25, 2017 Wunderbar! One correction: the chip removed from the motherboard is a 74LS42. 1 Quote Link to comment Share on other sites More sharing options...
+tf_hh Posted June 25, 2017 Author Share Posted June 25, 2017 Wunderbar! One correction: the chip removed from the motherboard is a 74LS42. - Thanks, I wrote this wrong. It´s the 74LS42 chip, the middle one below the RAM card slot Jurgen Quote Link to comment Share on other sites More sharing options...
jvas Posted June 25, 2017 Share Posted June 25, 2017 Hi, Interested in 1 piece. Thanks: Jozsi Quote Link to comment Share on other sites More sharing options...
Roydea6 Posted June 26, 2017 Share Posted June 26, 2017 Hi Jurgen I would like to get one card. Thanx!! Quote Link to comment Share on other sites More sharing options...
Bunsen Posted June 26, 2017 Share Posted June 26, 2017 Looks amazing! I want one :-) Quote Link to comment Share on other sites More sharing options...
Marius Posted June 26, 2017 Share Posted June 26, 2017 VERY interested. Please do not ship with DHL/Deutsche post to me though Use UPS instead. I know, more expensive...but also way more reliable. Count me 1 for 1 please. Thanks Marius Quote Link to comment Share on other sites More sharing options...
1050 Posted June 26, 2017 Share Posted June 26, 2017 I'll take one too. Quote Link to comment Share on other sites More sharing options...
+JAC! Posted June 27, 2017 Share Posted June 27, 2017 (Ne, ne, ne ... Wann macht der das alles...) Quote Link to comment Share on other sites More sharing options...
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