= Part Calculation of Electronics Digram =
== LED's for crossroad ==
* the datasheet of the DSP implemented on the Explorer Board 16 (see pages 1 & 273) indicates that :
** output current of I/O : I = 10mA
** voltage I/O : VDD = 3.3V
* the datasheet of the red LED (see pages 3) indicates that :
** conduction voltage : VF = 1.8V
** average current : I = 20mA
=== Formula ===
* calculation of resistance RD <math>\frac{U_r}{I} = \frac{VDD - U_{LR}}{I} = \frac{3.3V - 1.8V}{10mA}</math> = 150mA
= Layout =