9s12 wake up by XIRQ

[jiongzhongliu]

Now I use the MCU MC9S12XET256,  when the MCU in the Stop or Wait Mode ,I can wake it up by a input Interrupt(PP2),Now I want to wake it up by the PIN XIRQ, which regiter or instruction I should program before it go to stop or wait mode., The datasheet say XIRQ enable by cleaer the X-BIt in CPU conditon code register,and I don't particularly understand.

[RadekS]

Hi jiongzhong,

X bit is part of CCR register (Condition code register, one of CPU’s basic registers).

You could clear this bit similar way how you clear S bit prior STOP mode.

So, for example:

asm ANDCC #0x7F; //clear S bit

asm ANDCC #0xBF; //clear X bit

or

asm ANDCC #0x3F; //clear S and X bit

For more detail, please see CPU12X reference manual:

http://www.nxp.com/files/microcontrollers/doc/ref_manual/S12XCPUV2.pdf

I hope it helps you.

Have a great day,
RadekS

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