Atari 400: cpu and memory card

[tep392]

2 hours ago, johannesmutlu said:

Speaking about ram upgrades for the atari 400,for what i,ve readed is that early atari 400’s only did had 4KB of ram and that later atari 400 systems did had 16KB ram installed,now comes the wuestion,if i want to upgrade my atari 400 with extra ram like 48KB,do i really have to solder extra wires to make it work or is that soldering only required for audio in and out for cassette tapes???

also i,ve readed that first models of the atari 400 did had a ctia chip for a maximum of 128 colorpallet while later revisions of the atari 400 did contain a gtia chip for a maximum of 256 colorpallet,is this true? May ask why as it could cause confusion among sellers and buyers for whether their capabilities and compatibilities with certain games,

Not mention,many remodeled atari 8bit system do use their own os system,thus rendering more games to became incompatible with each other,may ask why,why didn’t atari just used 1 system rather then sneakingly upgrade them under the hud?? Now if only the atari XE,atari 800 or the atari 5200 was upgraded,it wouldn’t have caused that much confusion to anybody,

but because of this,it does makes me wonder wich games do take advantage of the 256 colorpallet and the extra ram and wich games did not and wich games did require a certain os system to make them work???

as far as i know,it’s a mess and a mix match of trial and error among consumers to decide what to buy and as far as i do know theres no way to upgrade the system to increase compatibility with more games without moddifying the whole system,maybe in some cases,

i ordered my atari 400 and i can only hope it’s the upgraded version with higher compatibility of certain games and also hope that it works anyways as it was untested,but it’s low price triggered me to buy it.

only time will tell whether i do regret buying it or not,

 

Maybe you will get lucky. I bought my 400 on ebay years ago and was happy to find it had an Intec 48K upgrade hidden inside that the seller did not know about.  Intec used a clever board to make installation a bit easier.

[reifsnyderb]

22 minutes ago, tep392 said:

Maybe you will get lucky. I bought my 400 on ebay years ago and was happy to find it had an Intec 48K upgrade hidden inside that the seller did not know about.  Intec used a clever board to make installation a bit easier.

I absolutely love the idea of that board.  However, it's not compatible with Atari's 48k upgrade.

[ClausB]

7 hours ago, johannesmutlu said:

early atari 400’s only did had 4KB of ram

Only the prototypes had 4K. Early production 400s had 8K. Later they had 16K.

[ClausB]

7 hours ago, johannesmutlu said:

first models of the atari 400 did had a ctia chip for a maximum of 128 colorpallet while later revisions of the atari 400 did contain a gtia chip for a maximum of 256 colorpallet,is this true?

Yes, that's true. Early 800s also had CTIA chips.

[tep392]

4 hours ago, reifsnyderb said:

I absolutely love the idea of that board.  However, it's not compatible with Atari's 48k upgrade.

I don't think so.  I just checked the connector signals.  This is the difference between the Atari and Intec motherboard wiring.

Atari        Intec
/S4 -> R    /S4 -> N
RD4 -> T    RD4 -> M
/S5 -> N    /S5 -> R
RD5 -> M    RD5 -> T

 

So basically Intec swapped R/T and N/M compared to Atari.  This looks functionally equivalent based on how the 48K boards are designed.

[reifsnyderb]

56 minutes ago, tep392 said:

I don't think so.  I just checked the connector signals.  This is the difference between the Atari and Intec motherboard wiring.

Atari        Intec
/S4 -> R    /S4 -> N
RD4 -> T    RD4 -> M
/S5 -> N    /S5 -> R
RD5 -> M    RD5 -> T

 

So basically Intec swapped R/T and N/M compared to Atari.  This looks functionally equivalent based on how the 48K boards are designed.

I just double-checked with a schematic that works with a 400.  You are right, it should work.

[ACML]

3 hours ago, ClausB said:

Yes, that's true. Early 800s also had CTIA chips.

My 1981 16K RAM 400 came with a CTIA.  I realized something was wrong when I bought the Atari Tennis cartridge.  If I remember correctly, the players had no clothes (body).  I took it into an Atari service center and they said it had a CTIA and replaced it with a GTIA.  Don't know if the CTIA was defective or all CTIAs would have the same issue with Atari Tennis.

 

[johannesmutlu]

On 10/11/2023 at 2:59 AM, ACML said:

My 1981 16K RAM 400 came with a CTIA.  I realized something was wrong when I bought the Atari Tennis cartridge.  If I remember correctly, the players had no clothes (body).  I took it into an Atari service center and they said it had a CTIA and replaced it with a GTIA.  Don't know if the CTIA was defective or all CTIAs would have the same issue with Atari Tennis.

 

Well i wouldn’t be surprised if the missing clothes from those players in that tennis game had something to do with the missing colorpallet from the ctia chip wich only has a 128 colorpallet while the gtia chip does contain a 256 colorpallet,so if that tennis game make use of the higher colorpallet from the gtia chip,then i wouldn’t be surprised about this.

and with this in mind,i wonder why didn’t atari just called their atari 400 with the sneakingly upgraded gtia chip the atari 400 + instead??? As that would,ve avoided so much confusion,especially if also those supported games did say on the box,atari 400 +,same problem with most atari 5200 4 plug models in case you want to use the 2600 adaptor with it,they should,ve called those final revisions of the atari 5200 the atari 5200 + instead,but sadly they didn’t🥲🥲