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More eggs
Posted: Wed Apr 22, 2020 9:23 pm
by Milli
Re: More eggs
Posted: Fri Apr 24, 2020 11:06 am
by joltguy
Wow check this one out!
The SmartWriter word processor contains a remarkable subroutine called right after the power-up routines which bank-switch in this ROM and jump to the first byte of initialization code. Coleco made a 300-baud internal modem for the ADAM (ADAMlink); every time you turn on the computer the modem is initialized, and then the modem port is read: if a valid ROM signature AAh 55h is received, then it assumes that a cartridge game program is being fed in through the modem! The next 2 bytes are the load address, and the next 2 after that the length of the code; it is loaded in, the game operating system ROM switched in, and it jumps to the start of the game! Someone suggested that perhaps Coleco was planning a company BBS whereby someone calling in with the ADAMlink modem could try out game demos by pulling the reset on the computer at the appropriate moment while on-line!
From this page:
http://www.digitpress.com/eastereggs/cvadam.htm
Re: More eggs
Posted: Sat Apr 25, 2020 5:55 am
by Milli
That is cool - we should test it.
Re: More eggs
Posted: Sun Apr 26, 2020 5:54 am
by joltguy
I would love to try it out and see if it works. I have an ADAMLink modem and the cable for it. I was thinking that I could use it to connect to a mock "BBS" that I would set up which only sends the 0xAA 0x55 and other required bytes upon connection (including cartridge ROM bytes). The problem is that resetting the ADAM to start up SmartWriter would drop the connection. Not quite sure how to get around that yet.
Re: More eggs
Posted: Sun Apr 26, 2020 9:40 pm
by Milli
Yeah good point. What about cutting the reset line in the modem?
Re: More eggs
Posted: Mon Apr 27, 2020 7:47 am
by joltguy
That's an interesting idea... although I do wonder how this concept was originally supposed to work without that type of modification.
So... when the reset switch is pulled the ADAM doesn't actually power cycle? It just clears memory and sends a "reset" message to the ADAMnet?
Re: More eggs
Posted: Mon Apr 27, 2020 8:08 am
by Milli
No wait I don't think it will drop the connection. I remember back when I was testing things a few years ago connecting the adam to a pc directly via the phone cable you can make the connection with Adamlink, then put in a CP/M tape and hit reset and the connection was still there. I used it so I could use PIP to transfer things before I figured how to "answer" the modem in M/L.
Re: More eggs
Posted: Mon Apr 27, 2020 11:21 am
by joltguy
Oooh nice, that's great! So there really is the potential for this to work. At 300 baud I figure it'd take just over 14 minutes to download 32k so it wouldn't be fast but I still think its a cool concept.
Re: More eggs
Posted: Mon Apr 27, 2020 5:42 pm
by Milli
I think the biggest issue will be the timing
Re: More eggs
Posted: Mon May 25, 2020 3:11 pm
by joltguy
Looks like its a good thing we didn't spend too much time on this. While searching around for some Adam info unrelated to this Easter egg I just happened to come across
This Week With My Coleco ADAM 9710.20.
If you scroll down on that page you'll find a section titled "Code Fossil: ADAMlink Modem I/O in SmartWriter" that contains all the details including this unfortunate note:
As noted in the code comments, there's no way that this can work with the ADAMlink modem as we now have it; there's no handshaking for any of the modem data port reads. So, if you try to set this up now, with a second computer ready to send a program at 300 bps, it will fail.
The same article contains the original speculation about a planned Coleco online service.