The practice of using software to literally toggle (or read) individual pins with the correct software-controlled timing in order to communicate with some hardw

The practice of using software to literally toggle (or read) individual pins with the correct software-controlled timing in order to communicate with some hardware. To transmit a bit pattern 10010010 over a single pin channel, for example, you'd literally set the pin high, sleep for a some predetermined amount of time, set it low, sleep, set it low, sleep, set it high, etc.