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Post by MadModder on Aug 23, 2006 19:55:22 GMT -5
After seeing several photos of that QLink stuff and modem games I thought -Hey, I want that too! So I build this... thing. Found a schematic here (zip file)One side of the PCBBack side of box, and PCB mountedThe whole thingThe switch is for de/activating the DSR line. The text says it's for some software. And it slides right inHere's my schematic. It's almost the same. And those two ICs' (75C188 and 75C189) are the same as MAX232, except it's four receivers in one chip, and foure line drivers in another. And they're cheaper. Why use internal DC-DC-converters when you have 9VAC which you can use to get +/-12V... It works in that way it didn't fry my C64, and the box did not disappear in a cloud of smoke, hehe. That's promising Now I just have to make a null modem cable, and fire up some terminals. Maybe tomorrow...
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Post by MadModder on Aug 24, 2006 7:56:23 GMT -5
Ok. One cable made and tested. I have tried transferring raw text both ways in 2400bps, and it works. No garbage. I haven't figured out how to transfer files though. Maybe hyper terminal in windows sucks... CCGMS just says bad blocks.
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Post by tlr on Sept 1, 2006 16:44:18 GMT -5
Ok. One cable made and tested. I have tried transferring raw text both ways in 2400bps, and it works. No garbage. I haven't figured out how to transfer files though. Maybe hyper terminal in windows sucks... CCGMS just says bad blocks. For serial transfers with this kind of interface try over5. It does 38k4.
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Post by MadModder on Sept 1, 2006 17:46:50 GMT -5
Ok, i'll try that. Do you know if there's any program that tests every signal in a fully connected serial cable, on both sides? Can I use full handshaking with over5 ( too see that everything works. RTS,CTS, DTR, DSR) BTW, I thought about the outputs on the C64. Aren't they open collectors, with pullups? I took the LEDs off, because i realized they act as pulldowns. I knew that, but didn't think about it. I'll change that later.... but there was no difference.
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Post by tlr on Sept 2, 2006 3:15:43 GMT -5
Can I use full handshaking with over5 ( too see that everything works. RTS,CTS, DTR, DSR) Over5 does not use hardware level handshaking.
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Post by MadModder on Mar 19, 2007 11:35:35 GMT -5
I thought I finally would fix those LEDs in the adapter. They act as pulldowns to the lines coming from the C64. Not good. A few transistor will do the trick. BUT! Something caught my eye just after removing the lid. The idea was to use this particular pad as a via to the other side. Guess what? No contact! ;D This is TXD, which makes it VERY strange that I got some data through at all...
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Post by David Murray on Mar 19, 2007 12:06:00 GMT -5
I may be building one of these myself eventually. I have been unsuccessfull in getting my RS232 unit to work. however, when I was working with Amiga Explorer last week I found it wouldn't work because the null-modem cable I was using wasn't wired properly. It would work in a terminal program, but not with Amiga Explorer due to the RTS/CTS lines. So I cut the ends off and soldered new ones based on the designs from Amiga Explorer's documentation. It works now. I'm going to try it on my C64 soon and see if the different wiring will help it. If not, I guess I'll throw it in the trash and build a new one.
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Post by Jim Brain on Mar 19, 2007 16:45:53 GMT -5
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Post by MadModder on Mar 20, 2007 16:33:21 GMT -5
If I don't count my status LEDs with it's resistors (you don't have any) I have fewer parts on my board. Or maybe you didn't mean that?
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Post by Jim Brain on Mar 21, 2007 0:34:50 GMT -5
The board can be assembled without some of the components, they are optional.
Jim
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Post by David Murray on Mar 21, 2007 7:01:18 GMT -5
The one that will be the real winner is the one who has a kit or a pre-drilled/etched board available!!!
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Post by Jim Brain on Mar 21, 2007 10:34:09 GMT -5
I sent EAGLE BRD and SCH files to DoppleGanger, who is making Link232 and EZ232 boards for sale, as I recall.
Jim
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Post by Golan Klinger on Mar 21, 2007 11:16:08 GMT -5
I sent EAGLE BRD and SCH files to DoppleGanger, who is making Link232 and EZ232 boards for sale, as I recall. Yep. See here.
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Post by MadModder on Mar 25, 2007 6:34:41 GMT -5
While fixing the solder fault, I decided to finally fix the LEDs. Since the 6526 can only source 1mA/pin (according to the datasheet), the LEDs on the outputs pulled the voltage down too far. Solution : buffer transistors. Not very nice looking, but it doesn't show when the box is closed. If you wonder about that unsoldered pad to the right, it doesn't go anywhere on that side, so I didn't bother. And with a few rub-on letters, I can see what the LEDs tell me
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Post by Golan Klinger on Mar 25, 2007 10:50:02 GMT -5
You know, MadModder, you really are an artist. That looks like a commercially made product and a very high-quality commercially made product at that.
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