串口中断接收，IntMasterEnable是否是必须的？

ebuffalo

串口中断接收，IntMasterEnable是否是必须的？ [复制链接]

刚做了串口中断的小程序，发现IntMasterEnable加不加都可以。串口中断接收，IntMasterEnable是否是必须的？

brucege888

我也觉得系统上电后，好像默认总中断是打开的。。

beloved

Cortex-M3上电默认是允许中断的到其内核的。

//! \return Returns \b true if interrupts were disabled when the function was
//! called or \b false if they were initially enabled.
//
//*****************************************************************************
tBoolean
IntMasterEnable(void)
{
//
// Enable processor interrupts.
//
return(CPUcpsie());
}

#if defined(ccs)
unsigned long
CPUcpsie(void)
{
//
// Read PRIMASK and enable interrupts.
//
__asm(" mrs    r0, PRIMASK\n"
      " cpsie i\n"
      " bx    lr\n");

//
// The following keeps the compiler happy, because it wants to see a
// return value from this function.  It will generate code to return
// a zero.  However, the real return is the "bx lr" above, so the
// return(0) is never executed and the function returns with the value
// you expect in R0.
//
return(0);
}
#endif

[ 本帖最后由 beloved 于 2011-7-27 10:03 编辑 ]