newman (11/23/82)
Thanks to those who responded to my Atari 400 questions a while ago. Brief
summary below. However, no one got the non-Atari cassette deck answer quite
right (I did some digging and found out the story).
- Yes, you can get at separate composite video and sound signals in the 400,
since the 800 makes them available and the 400 is identical internally.
You would have to open it up and goof around with the schematics though.
- It would be difficult to use a non-Atari 410 cassette player with the 400/800
because they pull a neat trick on the cassette I/O. The computer spits out
encoded audio (FSK, something like 3992 and 5327 Hz, 600 baud) to the 410,
but what the 410 sends to the 400/800 is TTL-level (0 and +5 volts)! So the
410 converts the FSK stuff to TTL-level itself. Actually this could be a
very nice way to download to the Atari, and it also should be quite easy
to read Atari tapes from a 410, given an I/O line and the tape record format.
- You can use 810/815 disks with the 400, possibly even with 16K, but then you
wouldn't have much room for Basic. Memory expansion cards to 48K exist, but
are not without problems. The thing about the 400 is that there is only room
for one card, so to get 48K you have to remove the Atari 16K board and put
in a 48K board. These cards can cause problems with screen clarity, either
because of power supply limitations or RFI due to poor components/layout.
Putting 48K on such a small board is no picnic (they use 4116's I think).
The Mosaic 32K board is supposed to be excellent, and it comes populated
with 16K - the other 16K you pull out of your Atari board.
- Many reference manuals for the Atari 400/800 exist, the Hardware/OS manual,
the Atari Technical Manual (for assembler prog. info), the book De Re Atari,
etc.; commented OS ROM and DOS listings are available from Atari.
You can get a couple of different keyboards for the 400 that I know of; a new
one coming out soon costs only around $100, and installs in 5 minutes. New
games I've heard are coming soon are Zaxxon, Donkey Kong, Tron, E.T. (?!), and
Defender.
Ken Newman
Univ. of Toronto