This example gives a functional emulation of a scanning LED array. Here a row of LEDs will light in turn one after the other. The circuit uses the PA port PA0~PA7, each bit of which is connected via a 240Ω series resistor to an LED.-This example gives a functional emulation of a scanning LED array. Here a row of LEDs will light in turn one after the other. The circuit uses the PA port PA0~PA7, each bit of which is connected via a 240Ω　series resistor to an LED.