topic S12X Setting the U bit in the Condition Code Register in S12 / MagniV Microcontrollers

S12X Setting the U bit in the Condition Code Register

Pedro_ — Thu, 03 Jul 2008 21:10:22 GMT

Hi all,

this is probably an easy question for some of you.

How do I set the U bit in the Condition Code Register?

I was trying transfering the content to the D accumulator, setting there and back to the CCR, but it doesn't seem to work for the upper byte.

Thanks

Pedro

MJW — Thu, 29 Oct 2020 09:18:27 GMT

Hello Pedro,

to set the U-bit you can, for example, do this:

Code:

    TFR          CCRH,A    ORAA       #$80    TFR          A,CCRH

or, without using an extra register:

Code:

    PSHCW
    BSET        0,SP,#$80
    PULCW

HTH,
MJW

Pedro_ — Thu, 03 Jul 2008 22:21:46 GMT

Thanks MJW !