HardwiredSerialPorts

Hardwired Serial Ports

Basically, not a USB serial port. How so, I hear you ask?

Well, in days gone by the USB port had not been invented and modems were big, pug-ugly boxes that lived outside your PC and connected you to the outside world with a staggering 1.2Kbit/s. To connect this thing to your computer (not a PC - they'd not been invented yet), you used the same interface that banks used to connect up the terminals - RS232. When PCs came along, they wanted to connect as terminals too, and wanted to use modems. So they had RS232 ports On a plug-in card. Someone invented the mouse, so they needed two plugs. Chips merged, providing two standard serial ports, and these spread into 386 PCs Pentiums, and now ... now nobody uses them much. Chips are cheap, boxes and connectors are expensive. So, there are fewer manufacturers sticking RS232 connectors in their boxes these days.

When you have one in your PC's box, you can dicker with the control lines in computer-space. For one on a USB, the serial port's USB controller runs a little network. Your PC doesn't have absolute say over how the serial port works anymore and the USB gizmo handles the control lines as it sees fit.

A common dodge used to be to use the signal lines - not the data line - of a serial port connector to make electronic add-ons do their stuff. So it is with our PIC programmer. So if you don't have direct control over the serial port, the PIC programmer isn't going to be able to do its stuff.

You're not beat yet. Pay enough money and you can buy a PIC programmer that works through the USB port. Probably not under Linux though - correct me if I'm wrong, it is a Wiki after all.

Pay out slightly less money and you can buy PCI cards that plug in to a PC and give it serial ports - tough on laptop owners though. One word of advice: Don't expect logical number ing of the ports. A Linux PC will probably have the first two serial ports as /dev/ttyS0 and /dev/ttyS1. But a plug in PCI card may start its serial ports at /dev/ttyS14 and /dev/ttyS15. Once you've booted your PC, check the output of the dmsg command and look for likely suspects.

For free, you can use an old computer, which probably has a working serial port on it.

Or, you could do the work to make a USB serial PIC Programmer work under Java, which Simon and I would probably be quite greatful for. Oh, a whole bunch of Laptop and Mac users would probably like it too.

-- Main.VikOlliver - 07 May 2006