1541 to parallel adapters

[NeXT]

I was doing research on why someone snapped up a 1541 II from me for a questionable price and noticed mention that you can put a parallel port on almost any 1541 and use that with a PC to read and dump disk images. Further research showed complex boards with USB and Commodore serial, small boards with A parallel port, several stupid small transistors and a commodore serial port and mention that you could simply wire a parallel port directly to a VIA chip in the drive...followed by photographs of people putting DB15 connectors instead of DB25 connectors on the side or back of the drive for the PC to plug into.
Is there really nothing to this besides a parallel port, ribbon cable, and solder? I'm swimming in 1541 drives. I must know what's going on here so I can really have fun with my Commodore 64 and 128.

 

[Chuck(G)]

A couple of decades old at least, I think. I mounted a DB25 connector on a 1571 (double-sided is nice) and use the circutry for a XE1541 cable in the drive. Allows me to use a straight 25-conductor cable without thinking about it.

The only problem is that it's slower than using a Catweasel to read the disks directly.

 

[carlsson]

It appears you are asking many questions at the same time.

1. The X-series cables have been around since the 1990's. The first one was X1541, a straight cable from PC LPT to 1541 IEC. That cable is mostly usable with 486 and below. The next cable was XE1541, which adds four diodes in order to be more reliable on Pentiums. The next cable was XM1541, a variant of XE where the diodes have swapped places in order to use the cable with Windows, Linux and other multitasking operating systems. The next cable was XA1541, which substitutes the diodes for "stupid small transistors" for improved compatibility with "stupid Chinese chipsets" found on some newer PC's. Then there have been a few more variations like the XU and XUM to move from "stupid big parallel ports" to "stupid smaller USB ports".

2. You can hack your 1541, 1571 etc with a parallel interface to shuffle data faster. This has been done since the 1980's, and is common with some speed loaders. Many of the X-series cables mentioned above are available in P-versions to take advantage of a hacked drive. It is highly optional, but will of course make things run faster.

I don't know if you want to hack drives to add the parallel port and some illegal copy of Dolphin DOS, Professional DOS or whatever might float around. To set up a virgin drive with a regular X-series cable is easy though.

 

[salamontagne]

Thanks, Ive been looking around for some more info on the X series of cables.

Do you know if x1541 and the program that came with it supports the "autostart" feature of the c128? Does any of the cables allow passthru mode? (IE hookup one end of the cable to the virgin drive, connect the drive to commie, and the link will be able to host disk images (as drive 9 or ten), and be able to make images off of drive 8?

as far as adding the 25pin parallel port hack to the drive, is this faster then actuall running the x1541 cable? do you have any links as how todo it?

Another thing i wanted to know... How well does the copy protection take it when your useing one of these methods.

Sorry about the long, instnse post, but my "rescued" C128D has been calling me...

It appears you are asking many questions at the same time.

1. The X-series cables have been around since the 1990's. The first one was X1541, a straight cable from PC LPT to 1541 IEC. That cable is mostly usable with 486 and below. The next cable was XE1541, which adds four diodes in order to be more reliable on Pentiums. The next cable was XM1541, a variant of XE where the diodes have swapped places in order to use the cable with Windows, Linux and other multitasking operating systems. The next cable was XA1541, which substitutes the diodes for "stupid small transistors" for improved compatibility with "stupid Chinese chipsets" found on some newer PC's. Then there have been a few more variations like the XU and XUM to move from "stupid big parallel ports" to "stupid smaller USB ports".

2. You can hack your 1541, 1571 etc with a parallel interface to shuffle data faster. This has been done since the 1980's, and is common with some speed loaders. Many of the X-series cables mentioned above are available in P-versions to take advantage of a hacked drive. It is highly optional, but will of course make things run faster.

I don't know if you want to hack drives to add the parallel port and some illegal copy of Dolphin DOS, Professional DOS or whatever might float around. To set up a virgin drive with a regular X-series cable is easy though.

 

[carlsson]

The C128 autostart looks for a certain type of file on the floppy disk. I don't see any problem for one of the PC programs used to transfer disk images to include a such file if it is present on the disk image. However the cable itself or the transfer program probably can't generate an autostart file of your liking. You have to look for that in more detail.

As for passthru, you should be careful to connect two master devices (computers) to the same slave (drive). This is due to the bus can be held high. There are certain POKEs on the Commodore side to release the ATN, so another device can use it. This is the same no matter if you connect two C64's to the same drive or one of them is a PC with X-series cable.

However it appears the XU adapter has two IEC ports, so maybe that design somehow lets you chain it inbetween C= computer and drive. Again, that is something which requires research to say for sure.

When you ask for the PC to act like a host, you are mostly restricted to 64HDD in DOS mode. That program will only work with the X and XE variations of the cable, and as I wrote above, you would have to read its docs to know if and how to add a 1541 in the mix. I think you would have bus issues.

The main page about X-series cables is here: http://sta.c64.org/xcables.html

Basically you need e.g. one XM1541 cable and one XP1541 (or a combined XMP1541) in order to use a parallel port enhanced 1541. The page says it triples the transfer speed. As you will see when browsing that page, it has instructions how to hack the drive, which is where the DB15 comes into play, in case more people than NeXT were confused about that.

Finally, when it comes to advanced copy protection you seem to need a parallel enhanced drive:
http://c64preservation.com/dp.php?pg=faq
http://c64preservation.com/dp.php?pg=nibtools

 

[NeXT]

Okay, so I made up two of the solderless 1541 parallel adapters today but still, why the DB15 parallel connector?
They don't even give the alternate pinout/conversions for DB25 either.

 

[carlsson]

The DB15 connector would originally connect to the userport of e.g. a C64 equipped with custom ROMs like Dolphin DOS or Speed DOS, or one of the standalone copying programs like 15 Second Copy, Burst Nibbler, Maverick etc. I don't think it ever was intended to hack a 1541 to connect to a PC at that time, and in any case you need a way to connect the IEC serial cable too as the DB15 parallel cable only assists in transfer speed, it can't be used to send commands to the drive.

Here are the details how to build a parallel cable between 1541 and C64, assuming the 1541 internally has been modified so the DB15 leads anywhere.
http://sta.c64.org/cbmparc2.html

Here are the details how to "convert" DB15 to DB25, but in order to use that with your PC, you will need to have two parallel ports on your PC.
http://sta.c64.org/xp1541c2.html

Finally here are the details how to build a combined XEP1541, which will utilize one parallel port on your PC in order to connect both to the IEC serial and the parallel.
http://sta.c64.org/xep1541ac.html

However as you will see in the diagram, it assumes your 1541 parallel connector is a card edge one, the one you usually would connect into the C64 user port. Normally you would build or already have that cable as you want to take advantage of the parallel capacities with a C64 as well as the PC. However if you are only interested in connecting a 1541 to the PC and get as fast transfer speeds as possible, you would have to trace the pinout of the DB15 and card edge connectors (see above links) and in the XEP1541 adapter cable replace the card edge connector with a DB15 and connect a straight DB15 cable with at least 10 of the 15 pins connected.