When trying to accomplish something with technology, it seems like there are always these strange "gotchas". I've encountered the first on my road to a PX-8 virtual drive prototype...
As I set out to produce the PX-8 virtual floppy drive, one resource that I'm hoping to use for reference is the open source, Linux-based "vfloppy" program (see previous post). Turns out, vfloppy works great on my old Dell laptop, but not on my newer one (Dell D630). Both are running Ubuntu 10.04 LTS, both have the same serial UART, and they are configured identically. However, with the D630, I get serial communication errors, and with the older Dell Inspiron, I don't. Ugh.
Since I've got the source code, I went poking around to see how the serial port is initialized and opened in the vfloppy program (epspdv3.c). It's pretty straightforward stuff using the standard libraries. Should be about as hardware non-specific as you can get.
Thinking it might be my specific D630, I tested another that I had handy. Same issue. So the problem is not with faulty hardware, but with some specific hardware/software issue.
I know problems come up when trying to accomplish something - it's part of the challenge of a project. But this is my least favorite kind of problem, because it is, at best, only a tangent to the real problem I'm trying to solve.
I might just be stuck using my older laptop for the project, unless some magic happens...
I believe that there is some issue with supplying enough voltage from laptop serial ports. This: http://www.qsl.net/eb4eqa/serial_booster/serial_booster.htm was all I could easily find on google about it. Some newer laptops apparently have low power serial ports and thus have difficult with devices drawing more power and maybe also with communicating properly. Not certain, but maybe that's part of the problem.
You can use a cheap serial - USB converter, making it future-proof. All the ones I found work with epspd(v3).
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