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What good is an 850?

850 interface

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#1 Dripfree OFFLINE  

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Posted Sun May 5, 2013 9:01 PM

So when I picked up my 800xl It came with an 850 interface. Sweet right? It didn't come with anything to attach to it. Just wondering if anyone knows of something cool I could do with this? It's sitting on a shelf now and that makes me sad. Is there anything really cool I could get to attach to it? Any sweet hacks? I'd love to make use of it. I was actually considering cannibalizing the SIO ports when I was building my SIO2PC but I thought that would be a waste. I'm glad I didn't but I'm just not sure what else I'll ever use it for. I'm curious how other 850 owners are using it.

Edited by Dripfree, Sun May 5, 2013 9:05 PM.


#2 BillC OFFLINE  

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Posted Sun May 5, 2013 9:29 PM

So when I picked up my 800xl It came with an 850 interface. Sweet right? It didn't come with anything to attach to it. Just wondering if anyone knows of something cool I could do with this? It's sitting on a shelf now and that makes me sad. Is there anything really cool I could get to attach to it? Any sweet hacks? I'd love to make use of it. I was actually considering cannibalizing the SIO ports when I was building my SIO2PC but I thought that would be a waste. I'm glad I didn't but I'm just not sure what else I'll ever use it for. I'm curious how other 850 owners are using it.

The 850 has 4 serial ports, one for connecting RS-232 modems, and also a Centronics compatible parallel printer port. All ports have a different pinout than the PC standard and require special cables. Prior to getting a PC clone in 1996 I used a serial modem with an 800XL & MIO for dial-up to CompuServe.

#3 Marius OFFLINE  

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Posted Mon May 6, 2013 2:36 AM

Imo the Atari 850 is the most intelligent, versatile and standards compatible peripheral Atari ever released.

I use mine to connect a brother laserprinter and a lantronix mss 100 to my atari.

#4 thorfdbg OFFLINE  

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Posted Mon May 6, 2013 8:14 AM

Imo the Atari 850 is the most intelligent, versatile and standards compatible peripheral Atari ever released.


Yes, but... The 850 P: interface comes with a fixed-wired EOL->LF translation which can be more hurting than helping if you print graphics. There was an extended version by a third party vendor called the 850XL which had a software-switchable translation.The second drawback is that you cannot really use the 850 with hardware handshake, or anything else on the SIO port active while a serial transfer is running. The 850 serial interface has only two modes: The "short block mode" within which one can only write data out with 300 baud, and check the status of the lines, and the "concurrent mode" which allows input and output, but has no means of checking the status of the handshake lines, and all other devices on the SIO chain are not reachable.Thus, one has to use wierd workarounds to get the 850 integrated...

#5 wood_jl OFFLINE  

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Posted Mon May 6, 2013 1:24 PM

Although I don't use the serial port much anymore (since the modem days), I think the 850 is worth it just for the parallel printer interface, if nothing else.
Though there are other printer interfaces on the market:

(1) The 850 has a pass-through SIO port, so it's not the end-of-the-line.
(2) The fact that it has its own power supply means it leaves SIO power to operate SIO2SD or Sdrive, etc.

The ICD P:R: Connection and the Supra/MPP 1150 both have pass-through SIO ports, but run from SIO power. Perhaps SIO power is enough to power this and other devices, but I like the 850 running on its own power.

I never had problems with the EOL-LF translation, but I admit I haven't printed with an A8 in a while. I usually just set a DIP switch on the printer for auto CR-LF, and was fine. When moving that printer to other computers (Atari ST, and just about everything else) the printer's DIP switch would have to be set back to separate CR and LF.

#6 Dripfree OFFLINE  

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Posted Mon May 6, 2013 4:07 PM

Hmm well I'm thinking I will never have a real use for this I'm never going to use a modem, and if I were to get a vintage printer I think I'd get a 1027. I was thinking last night what if I took my rs232 sio2pc connected the serial end to one of the 850's serial port then soldered the sio end to one of the sio ports. Then I could just use a serial extension cable to connect my pc to my 850........ Maybe I could even take my sio2usb, connect the sio end to the sio of the 850 and just install a usb end on the empty side of the 850..... I wouldn't really be using any of the 850's circuitry. Wouldn't even have to plug it in. I a way I suppose I'd just be making an upgrade where it still fulfills it's intended purpose making the atari able to connect to more standard interfaces. Maybe its stupid but I'd like to make some use of the thing it's kinda pointless just sitting on a shelf.

#7 oracle_jedi OFFLINE  

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Posted Tue May 7, 2013 12:35 AM

You can also use the 850 to connect your Atari to a Linux server with an RS232 port, and then use a terminal emulator like Ice-T to connect to Linux from your Atari.

Of very questionable use I know, but it was a blast connecting to the company servers and then launching SQL*Plus to connect to a production Oracle database, all from my Atari 1200XL.

BTW. DONT buy a 1027 if you plan to actually print anything, the chances of an operational print head are about zero.

#8 thorfdbg OFFLINE  

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Posted Tue May 7, 2013 3:13 AM

<p>

You can also use the 850 to connect your Atari to a Linux server with an RS232 port, and then use a terminal emulator like Ice-T to connect to Linux from your Atari.

This is actually how I did use my 850XL, namely to transmit all the disks I have from the Atari to my Linux box to archive them there. But this required some form of custom protocol as the 850 does not allow for hardware handshaking so easily for the reasons already given above.

#9 Frankie OFFLINE  

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Posted Tue May 7, 2013 5:49 PM

For me, when I got my first Atari in 83, an 850 was impossible to find. There was an 18 month wait. So I got the mpp modem and the mpp printer port/adapter. I'm thinking of getting an 850 now just because I could never get one before.

Frank

#10 labrat OFFLINE  

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Posted Tue May 7, 2013 6:21 PM

RS232 was still common until recently. I often think about running older equipment off of an A800 just for fun. But, I've never actually used my 850.

#11 sup8pdct OFFLINE  

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Posted Thu May 9, 2013 4:14 AM

Don't forget that port 4 is setup for a teletype printer. Anyone have one of those?????

James

#12 imajeff OFFLINE  

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Posted Thu May 9, 2013 2:21 PM

I don't fully comprehend what you (Dripfree) suggested trying with the 850 between various connections but from what I see they would not work. The biggest clue is when you say you wouldn't even have to turn it on. Somebody please explain better, if I misunderstood.

The atari has to 'boot' from the 850 to install special driver before it can control the rs232 i/o. Those become extra ports, not extension of the sio. I got the impression you thought it would 'bridge' the rs232 and sio ports, as the sio2pc does but it is way more complex. Sorry if it's just me but I couldn't even guess what this could mean: "just install a usb end on the empty side of the 850"

The 850 is certainly amazing in what it does, but I haven't heard of people hacking except maybe rewiring to standard connectors. I imagine I'd have fun patching the driver to be more useful, but I don't know if anyone has.

With that said, does anyone know a hack to modify driver so this can become an sio2pc on demand? That would be possible, just don't know how much it would take. I have one but haven't dug into it much.

#13 skr OFFLINE  

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Posted Thu May 9, 2013 3:55 PM

Don't forget that port 4 is setup for a teletype printer. Anyone have one of those?????


At least I have access to some of them: http://www.hell-kiel.de/
In August there is the night of museums, where they exhibit and show working teletypers. If one can tell me how to use an Atari 800 (XL) with 850 (I have one, not sure if it is working as I did not use it yet) with a teletyping machine I would contact those guys to setup a demo station for the next event.

#14 thorfdbg OFFLINE  

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Posted Fri May 10, 2013 1:06 PM

I got the impression you thought it would 'bridge' the rs232 and sio ports, as the sio2pc does but it is way more complex. Sorry if it's just me but I couldn't even guess what this could mean: "just install a usb end on the empty side of the 850"

The 850 is certainly amazing in what it does, but I haven't heard of people hacking except maybe rewiring to standard connectors. I imagine I'd have fun patching the driver to be more useful, but I don't know if anyone has.

With that said, does anyone know a hack to modify driver so this can become an sio2pc on demand?

Well, it's a bit more complex than this. The 850 in concurrent mode is actually not a very smart device. All it does is that it samples the SIO input and then mirrors the input at the output, and vice versa, by its 65x2 CPU operating in a tight loop.The actual serial clock etc. is generated by pokey, not by the 850, which is only little more than a cable in this mode. This is different in the short block mode in which the 850 does all the signal generation. The COMMAND line will then drop the 850 back into its "intelligent" mode.

Actually, Atari should have created the clock for the serial output on the 850, not the main unit, but they choose otherwise.

There are a couple of other problems: First of all, it is the firmware of the 850 that does the sampling, and you don't have access to it unless you reprogram the EPROM inside. Second, there is no COMMAND line equivalent on the RS 232 ports. You would need to modify the firmware to "hijack" one of the other serial pins. Third, while I haven't made the math, there is at least one potential problem, and that is the clocking of the device. AFAIK, the 850 runs with a lower clock speed than the main unit, and the software sampling of the SIO input and mirroring the data at the output might just not be fast enough to allow a robust 19200 baud communication. Note that one should sample at a noticably higher speed than the native 19200 clock to avoid clock-skews. Actually, if you look into the 850 manual, you'll see that natively it does not allow 19200 output. The corresponding configuration is also 9600 baud only - probably for exactly that reason.

That said, it's unclear whether it is possible to overcome these, but I haven't seen a hack like this, at least.

#15 Dripfree OFFLINE  

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Posted Fri May 10, 2013 11:22 PM

No I wasn't thinking of using the 850 circuitry at all. I was talking about disconnecting the sio ports from the 850 circuit board. Then disconnecting one of the din9 ports Then installing my sio2pc between one of the sio ports and the din9. Then connecting my sio2usb adapter to between one of the sio ports and a usb install on the empty side of the 850. I've looked at it and I think I could do it in a way where I could restore it to its original function if I really wanted to reconnect it. Or perhaps there is a way it could be a way to hacked where it could have a switch that flipped it from 850 mode to sio2pc mode. It seems like it should be fairly simple cuz you would just be switching the ports from going to to its original circuitry or the sio2pc circuit. But I wouldn't know how to do that so for now I'd just disconnect them from the 850 circuit board completely. :-D

I actually started a thread a while back asking if the 850 could be used as an rs232 interface and I learned it's fairly unfeasible. I'm trying to figure out a way to use this 850 one way or the other. :mad:

Edited by Dripfree, Fri May 10, 2013 11:40 PM.


#16 Mathy OFFLINE  

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Posted Sat May 11, 2013 2:42 PM

Or you take out the DB9 ports and "replace" them with SIO ports, turning the 850 into a SIO hub. (which BTW is easier said then done)

Mathy





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