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+# LED Dimming and RGB LED with BBC Micro:bit in C++
+
+_Captured: 2017-08-09 at 17:53 from [toriilab.blogspot.de](https://toriilab.blogspot.de/2017/03/led-dimming-and-rgb-led-with-bbc.html?m=1)_
+
+![](https://4.bp.blogspot.com/-9HapVc32m1c/WM7WKo0aDGI/AAAAAAAAB88/Ti9kCDStTJ8ItcqJ2bUCoC6eKk-Zs5F9QCLcB/s280/rgb2.png)
+
+PWM is used in LED dimming; as the duty cycle of a PWM signal increases, the average voltage and power provided by the PWM increases. The intensity of an LED can be varied by pulse-width modulating the voltage across the LED. Adjustments to the intensity of the LED are made by simply varying the duty cycle of the PWM signal driving the LED.  
+The BBC Micro:bit has the following pins. The pin name do not correspond to the pin names in software on the mbed C++ platform and are mapped by the following:
+
+Pin GPIO  
+MICROBIT_PIN_P0 P0_3  
+MICROBIT_PIN_P1 P0_2  
+MICROBIT_PIN_P2 P0_1  
+MICROBIT_PIN_P3 P0_4  
+MICROBIT_PIN_P4 P0_5   
+MICROBIT_PIN_P5 P0_17  
+MICROBIT_PIN_P6 P0_12  
+MICROBIT_PIN_P7 P0_11  
+MICROBIT_PIN_P8 P0_18  
+MICROBIT_PIN_P9 P0_10  
+MICROBIT_PIN_P10 P0_6  
+MICROBIT_PIN_P11 P0_26  
+MICROBIT_PIN_P12 P0_20  
+MICROBIT_PIN_P13 P0_23  
+MICROBIT_PIN_P14 P0_22  
+MICROBIT_PIN_P15 P0_21  
+MICROBIT_PIN_P16 P0_16  
+MICROBIT_PIN_P19 P0_0  
+MICROBIT_PIN_P20 P0_30
+
+For this project, I am using the micro:bit, zbit:toolbelt board, an LED and a potentiometer. For LED dimming, any of the following pins can be used both for the potentiometer and LED.
+
+Analog GPOIO Pins  
+MICROBIT_PIN_P0  
+MICROBIT_PIN_P1  
+MICROBIT_PIN_P2  
+MICROBIT_PIN_P3  
+MICROBIT_PIN_P4  
+MICROBIT_PIN_P10
+
+I connected MICROBIT_PIN_P10 which is in analog input mode to the potentiometer. The value returned as a result is then written as the duty cycle to the LED. The LED is connected to MICROBIT_PIN_P4 in PWM mode. The micro:bit is programmed with C++ on the mbed platform with the following code:
+
+![](https://2.bp.blogspot.com/-pEwLepbwpq0/WM7WhfiJ3iI/AAAAAAAAB9A/LwtHgF3tru4Us5JsrA3HSeUXUnRSjp--wCLcB/s280/rgb1.png)
+
+Since I'm using a RGB LED, the micro:bit can also be programmed to change the colour of the LED with a key press. A video demonstration is shown below.