我刚开始学430在编译下面代码的时候，IAR报错 Error[Pe020]: identifier "P1REN" is undefined E:workspacemain.c 12

#include "io430.h"
#include "intrinsics.h" int main( void )
{
  // Stop watchdog timer to prevent time out reset
  WDTCTL = WDTPW + WDTHOLD;
 
  P1DIR = 0x41;
  P1OUT = 0x09;
  P1REN = 0x08;
 
  while(1)
  {
    if(!(P1IN&0x08))
    {
       __delay_cycles(500000);
       if(!(P1IN&0x08))
       {
          while(!(P1IN&0x08));
          P1OUT ^= 0x41;
       }
    }
    
  }   return 0;
}
各位你们看看是什么情况啊，谢谢 此帖出自小平头技术问答