The STi7141 is a highly integrated SoC (systemon- chip) designed to meet the demanding needs of the interactive cable set top box market place. The STi7141 integrates all the major system functions into a single device, and provides world lea

使用PCF8574 P口拓展芯片来实现4*4按键扫描-Use PCF8574 P port expansion chip to achieve 4* 4 keypad scanning