LF: Re^n: long haul QSO's .. >> programming

[DL4YHF@aol.com]

Steve and Alberto,

in fact there is a bunch of Ring-0 drivers around to do the job.
I used one by Yariv Kaplan called "WinIO" which came along with all the sources and an interface DLL around. It does a nice job in my Windows PIC programmer. But as Windoze XP is knocking at some people's door, even this trick does not work anymore, really a mess... because direct access is the only way to set the TxD signal of the COM port to a constant HIGH- or LOW-level.

If you only need TWO output lines at the COM port (RTS and DTR), there is a way to control these lines via the Windoze API. One could use one line as clock, the other as a data line to drive a simple shift register. The shift clock can be the leading clock edge, and the output strobe can be the falling edge with a logic "1" on the data line (thinking of I2C-bus). 

IMO, the serial port will exist a bit longer than the "LPT" port, and if not, there are a couple of USB->"COM" interface chips available which do not require advanced programming because they look like ordinary "COM" ports to an application. Or, as suggested earlier, use a PIC16F628 which has a nice UART and (in a PIC programmer's world) a large RAM and code memory. You can even program PICs in "C" these days as I saw on SM6LKM's page.

73,  Wolf