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Atari 850 Interface


Dripfree

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Hey got what may be a silly question. I was looking into making an sio2serial interface for my newly accqired 800xl . I happen to have an atari 850 interface. I was wondering if there is anyway to use the 850 interface to connect through the serial port of a pc and perform the tasks of a built or purchased sio2serial of sio2usb interface? Not only would it be cheeper but it would be pretty cool too if it is att all possible. I assume if people had been doing this it would have been easier for me to find out how to do it so I have begun to think this can not be done, but figured Id put the question out here.

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Won't be possible.

 

850 only sends data through it's RS232 ports when a SIO command directed to the 850 tells it to do so. ie - any SIO activity directed at other devices like disk drives, the 850 just ignores it.

 

SIO2PC type devices send the raw data unaltered, the RS232 types just convert the voltage levels.

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You could send files back and forth with terminal software with the 850 but you won't be able to do things like disk emulation. The 850 just gives you serial ports on the SIO bus. Think USB->RS232 interface in the modern age.

 

Trade ya a SIO2PC USB interface for that 850! LOL

Edited by kogden
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Won't be possible.

 

850 only sends data through it's RS232 ports when a SIO command directed to the 850 tells it to do so. ie - any SIO activity directed at other devices like disk drives, the 850 just ignores it.

 

SIO2PC type devices send the raw data unaltered, the RS232 types just convert the voltage levels.

 

Is it the 850 interface or the comm software or the driver that does that (ignoring other devices)?. If it's the software (either the comm software or the driver), then it may be possible to write a driver suitable for all SIO devices. As for the RS232 port, it's the same port used by the serial SIO2PC devices.

 

I am just speculating here as I never owned a 850 and don't know the details of the hardware.

 

In any case if you're thinking going serial (not USB), serial SIO2PC devices are not really that expensive. You can even build one yourself for even less.

Edited by atari8warez
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Is it the 850 interface or the comm software or the driver that does that (ignoring other devices)?. If it's the software (either the comm software or the driver), then it may be possible to write a driver suitable for all SIO devices. As for the RS232 port, it's the same port used by the serial SIO2PC devices.

 

I am just speculating here as I never owned a 850 and don't know the details of the hardware.

 

In any case if you're thinking going serial (not USB), serial SIO2PC devices are not really that expensive. You can even build one yourself for even less.

The 850 is designed for standard RS232 communication, Atari Data In/Data Out are translated to RxD/TxD. DCD/DTR/DSR/RTS/CTS/RI are used for handshaking with a modem, not for data. An SIO2PC device also connects the Atari Command signal to one of the handshaking signals, this allows software running on a connected PC to receive the Command Data and respond as an SIO device. Since the 850 doesn't connect the Command signal to an RS232 port signal it won't work as an SIO2PC device.

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  • 11 months later...

You can talk to just about any RS232 device you want to with it.

 

If that doesn't mean much to you then yeah.... collector's value.

 

You can talk to modems, RS232<->Ethernet devices like iPocket/LANtronix devices, servo controllers for robotics, serial ports on your PC/mac, etc.

 

It's simply an SIO<->RS232 serial device. Think USB<->serial adapter but 15 years before USB.

 

--Kevin

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You can build an SIO2PC USB version with nothing more than an SIO cable and a FT232RL breakout board from SparkFun for about $15. Just takes the 1 chip and the breakout board already has the mini-usb connector on it.

I'm interested - would ape be suitable for file transfers or what software would be best for this?

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I'm interested - would ape be suitable for file transfers or what software would be best for this?

APE "should" work. It just shows up as a serial port to the PC when you plug it in. Unless you want to pay for APE for some reason I'd just use Aspeqt.

 

On the mac side of things you can use SIO2OSX. There's a couple more disk emulators out there I believe.

 

So far mine have been incredibly reliable, even at ridiculous SIO speeds. I built one board into my 600XL and another I made by butchering an SIO cable.

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Interesting. Looking at the source code, it appears that the 850 is bit-banging two PIAs. There's over 1K in unused space in the ROM as well - anyone have any features they'd care to add?

Actually, it is a bit complicated how the 850 works. In its "normal" operation ("block mode") it receives data from SIO with all the device/control/command overhead and pushes data out of its serial port. Reading is not necessary. In "concurrent mode", it acts like a dump cable connection and the real timing comes from POKEY. The 850 main loop then just polls from its input line and mirrors the voltage level at its output. If the 850 CPU would run fast enough to create a reliable 19200 baud output, you *could* actually use this as a disk interface: Switch the 850 to concurrent mode, and use SIO. You won't get the "command" line on the serial port, though.

 

However, as the 850 cannot reliably operate under 19200, it is more a theoretical possibility.

 

As for the unused ROM space: The 850XL was a re-build from a manufacturer in Germany which dropped 3 out of the 4 serial ports, but added extended printing capabilities in the additional ROM area. It could translate the Atari graphics characters into Epson control sequences and would then print Atari graphics on every Epson compatible external printer. Translation could be turned off for graphics printing.

 

Greetings,

Thomas

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  • 2 months later...

The 850 is best used to connect to printers and modems, and other devices such as a teletype, which uses 20ma current loop..

 

SIO2PC type hardware SIO ->rs232 device is great for transferring data from/to disk drives. There is a can of worms I could open, but I choose NOT to do about the R:Verter serial device.

 

There are many ways to attach a modem, or other serial device. Research all this stuff, find out how the hardware works, and you will be fine.

 

-K

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The 850 is best used to connect to printers and modems, and other devices such as a teletype, which uses 20ma current loop..

 

SIO2PC type hardware SIO ->rs232 device is great for transferring data from/to disk drives. There is a can of worms I could open, but I choose NOT to do about the R:Verter serial device.

 

There are many ways to attach a modem, or other serial device. Research all this stuff, find out how the hardware works, and you will be fine.

 

-K

To transfer data between an 850 and a PC you will need either 2 modems or a null-modem adaptor/cable.

If you already have modem cables for the 850 and PC you can just get a DB25F/DB25F null modem adaptor, if you want to use a single cable you will need to custom make one as the 850 serial port uses a different pinout and gender than the PC.

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okay i'll get a null cable

 

and then use ape one the pc side

and what on the Atari side, please

 

thanks a lot

Walter

An 850 connection only allows you to transfer data, not emulate SIO devices. To use device emulators like APE/AspeQT you require an SIO2PC device.

 

If you want to use a null modem adaptor cable to transfer text files, which is what you mentioned in Post#16, you would use terminal programs on both sides. Hyperterminal is part of the Windows OS prior to Vista, and Bobterm or similar on the Atari side.

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so can I use something besides ape, to upload a file to the Atari, like I guess a term prog?

 

and download with another terminal on the Atari side?

 

 

Yes, actually you need exactly that. You need two programs on the PC and on the Atari that speak the same protocol for serial file transfer. Sorry that I cannot give any more concrete advice as to which software to pick - back then when I was in need for such a program, I just wrote my own and copied all my Atari disks to the PC. I would look into programs that speak one of the "?modem" protocols, i.e. xmodem,ymodem and zmodem. These are the best candidates.

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