Just like a PC’s USB port, the serial port on a PC can also in some cases serve as a power supply. A USB port can provide as much as 500 mA at 5V, but a serial port provides less power. Even with the ...

The Plan The plan is simple enough. A Linux program listens to a real serial port and watches for special character sequences in the data stream.

Anyway, I was assuming that I'd have to go out of the serial port and into a microcontroller of some kind to turn the bitstream into a raw voltage corresponding to percentage of processor usage.

So I'm trying to detect through Visual Basic 6.0 when a voltage change occurs on one of the pins of the serial/parallel port. The whole thing is pretty simple; no data transfer/handshaking/etc ...

The algorithm measures the durationbetween two consecutive rising edges.The microcontroller detects a risingedge or a falling edge when a receivedbyte is neither 0xff nor 0x00. If a byteis less than ...