Tim: >> Are you saying that unexpected data coming through your COM port >> wouldn't generate IRQ messages (COM ports have an IRQ), which would be >> kicking the CPU quite hard? That's not exactly a trivial thing to >> ignore. Mike McCarty: > The BIOS and MSDOS do not enable interrupts on the UART devices, > hence the CPU doesn't see any requests. > > Please don't lecture me about MSDOS systems programming. I wrote my > first interrupt driven serial comm package for MSDOS in 1985. Actually, I was asking a question, not giving a lecture, but since you've taken that attitude, answer this: In the BIOS you get to set the address and IRQ that a serial port will use. You can also set power wake up options that wake up the PC if a particular IRQ is activated. If you set it to wake up when the IRQ used by the serial port is activated (i.e. an external modem wake-on-ring type of function), the PC will wake up (serial port activity causing an IRQ signal, waking up the system). Now, *that* seems to refute your first assertion. (The serial port generated an IRQ signal, and the BIOS played a part in it.) -- (Currently running FC4, occasionally trying FC5.) Don't send private replies to my address, the mailbox is ignored. I read messages from the public lists.
