這在線路圖裡有4個外部中斷信號源(EINT0 ,EINT2,EINT11, EINT19)，

初始電位為高電位VDD_3V3。我們可以將GPIO PIN，GPB6和GBP7 設

定為低電位使得當按鍵被按下時，產生高電位轉低電位的電位轉態，

以作為觸發中斷的來源。

• 由線路號我們知道SW1 和SW5有相同的中斷信號EINT0，所以我們必

需要分辨當按鍵被按下時，有低電位產生，是來自SW1還是SW5，這

正是KEY SCAN的重點所在。-There are four external interrupt sources (EINT0, EINT2, EINT11, EINT19) in line Turi,

The initial potential of the high potential VDD_3V3. We can GPIO PIN, GPB6 and GBP7 located

Set at a low level so that when the button is pressed, the potential to generate a high potential to low potential transfer state,

As triggered the interrupt sources.

•　the line number we know SW1 and SW5 have the same interrupt signal EINT0, so we will

Need to distinguish when the button is pressed, there is low potential generated　SW1 or SW5, which

KEY SCAN s precisely the point.