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SIO2PC - The Next Generation

by David Davies

 

The SIO2PC has undergone a couple of redesigns since Nick Kennedy's original design introduced the idea of using a PC as a slave for the Atari 8-bit. The two-chip MAX-232 design was scaled down and replaced by a somewhat cheaper and simpler to build single-chip design. Certainly, I remember experiencing several problems getting the original design to work a few years ago, while a quick attempt to get the single-chip version working on a breadboard a few weeks ago yielded immediate hook-up with my laptop.

The design for the single-chip version I built was taken from the APE (Atari Peripheral Emulator) web site. The site also contained details of how to build a similar (but incompatible) cable to allow you to connect an original Atari 8-bit disk drive to a PC. With the APE ProSystem software running on your PC and a drive like the 1050 hooked up, you can create ATR files from your original disks. The ATR files can be loaded into just about any Atari 8-bit emulator. An extra feature of ProSystem is backing up your copy protected disks. But more on that later.

A few weeks ago, while browsing the AtariAge discussion board, I came across a few posts by the author of APE. At the bottom of his posts there were links to new pages on his site. One link went to a page giving details of his new flash ROM cartridges for the 8-bit and another gave access to a page with yet another version of the SIO2PC adapter.

Steve Tucker's new SIO2PC design is a combination of both the single-chip SIO2PC and the ProSystem cable. A problem with having two separate cables built is that plugging the wrong one into your Atari drive could damage it. Here is a solution that removes that worry as it will automatically switch between APE and ProSystem mode as necessary.

The unit itself is professionally produced and presently available in two versions. One includes a terminal block at one end to allow you to connect a cannibalised SIO cable for attaching it to the Atari. The other version, which is probably in limited supply, actually houses a 13-pin PCB-mounted SIO connector which allows you to use a normal SIO cable between the device and the Atari. This is the version I got my hands on.

It is on a lacquered PCB containing the usual 1489 chip, as used in the standard single-chip SIO2PC design, and a GAL programmed logic chip. The rest of the board contains a capacitor, two green LEDs, a red LED, a 9-pin serial socket for connecting to the PC and a 13-pin SIO socket for connecting to the 8-bit. The red LED is a power indicator and the two green LEDs indicate data transmission across the device.

One of the main problems with the unit is that it ships without any instructions, so it was pretty much a case of trial and error. In the end it took me about two hours to work out the sequence in order to get it to work properly.

One thing to remember is that the device doesn't take power from the PC. Your Atari must be switched on for it to work. This might sound obvious when using the APE software. However, it's not so obvious if you're using ProSystem. Even though you're accessing the disk drive from your PC, you still need the Atari connected to the drive and switched on to provide power. The SIO2PC should also be last in your device chain.

Something that many people might worry over is the fact that the device is not protected by an external cover or case. The PCB and parts are open to the world and may therefore be subject to damage from excessive handling or electrostatic discharge from the user's hands or clothing. To some extent the risks of such are over-hyped. Virtually all new semiconductors are designed to withstand an electrostatic discharge of at least 10,000 volts. But, of course, it doesn't mean that you should start testing the SIO2PC with your newly built stun gun!

So how well does it work? To put it into simple terms, it does what it says on the box. With ProSystem running I was able to use the 1050 to back-up a protected Atari disk onto the laptop and then use APE to load it back into the Atari. But I managed to hit a strange problem when creating ATR format files with ProSystem. Most refused to load into APE yet they ran fine on the Atari800Win Plus emulator. I contacted the author and he tested the software and hardware on his system, but reported that they worked fine. It may well be a testing issue but, let's face it, it's impossible to test every possible PC configuration - you just have to hope that the software works. As a case in point, a friend once bought me a copy of Populous: The Beginning a few years back. I couldn't get it to work on my system (blue screen of death every time) although it was well within the recommended specifications for the game.

Something that perhaps suggests a combination of issues related to the new SIO2PC design and the hardware I've had it running on is the fact that, although I didn't test it fully at the time, the original SIO2PC cable I built on the breadboard seemed to work fine. APE allows automatic configuration based on your hardware set-up. When the original design was connected to the laptop, the configuration option worked flawlessly. Now, with the new SIO2PC the PC completely locks up when I try to auto-configure.

However, I suspect that my problems may well be an isolated incident. All in all, if you haven't already got your hands on an SIO2PC of one form or another then Steve Tucker's version of the fabled cable is one well worth considering. Although more expensive than a home-built unit it has the advantage of being suitable for the SIO2PC software, APE and ProSystem. But for me the biggest advantage is that I don't have to slice up another much-needed SIO cable. But if you want one which doesn't require butchering an SIO then you may have to be quick to order one with a 13-pin SIO socket on the board as they are in limited supply.

Verdict

Name:

New SIO2PC

Developer:

Steve Tucker

Pros:

  • Only one interface needed to use either ProSystem or APE.
  • Little risk of damaging your hardware with two seperate home-built interfaces.
  • Reliable operation once set up properly.
  • No need to disect your own SIO cable if you opt for the version with the female SIO plug.

Cons:

  • No instructions (online instructions outdated and of little help).
  • No outer cover to prevent possible damage from mishandling or ESD.
  • APE/ProSystem software unintelligent.
  • Seemingly some compatibility issues on some PC systems.

Rating:

4/5


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MyAtari magazine - Review #1, April 2004

 
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