Difference between S12 and S12X

Started by drew...@gmail.com April 2, 2010
I have code written for a HCS12 Micro and was thinking about porting it over to a HCS12(X). It has interrupts, and it seems that the interrupts are handled differently. Is this true, or if the modules are the same between the 2 chips, will the code just port over and work the same.
Interrupts areh handled the same way, but when entering ISR, CPU pushes
additional byte to the stack. Thus if you are porting some preemptive RTOS
scheduler, you should take that into account.
New in S12X are also interrupt priorities. Your old code should work, unless
it performs a jump from some ISR to start of program. If that's the case and
your code contains such jump to start (software reset), then reinitializing
hardware you have to reset interrupt priority level in CPU status register.

Edward
----- Original Message -----
From:
To: <6...>
Sent: Friday, April 02, 2010 11:32 PM
Subject: [68HC12] Difference between S12 and S12X
>I have code written for a HCS12 Micro and was thinking about porting it
>over to a HCS12(X). It has interrupts, and it seems that the interrupts
>are handled differently. Is this true, or if the modules are the same
>between the 2 chips, will the code just port over and work the same.
>
First, an other (great) difference is the co-processor XGate, very
interesting !

Second, maybe your will have to re-compile your project, because, some port
addresses are not the same between S12 and S12X. Check the .H files of your
compiler to see the differences (or the data sheets).

Joel
-----Message d'origine-----
De: 6... [mailto:6...] De la part de
Edward Karpicz
Envoy samedi 3 avril 2010 07:06
: 6...
Objet: Re: [68HC12] Difference between S12 and S12X

Interrupts areh handled the same way, but when entering ISR, CPU pushes
additional byte to the stack. Thus if you are porting some preemptive RTOS
scheduler, you should take that into account.
New in S12X are also interrupt priorities. Your old code should work, unless

it performs a jump from some ISR to start of program. If that's the case and

your code contains such jump to start (software reset), then reinitializing
hardware you have to reset interrupt priority level in CPU status register.

Edward
----- Original Message -----
From:
To: <6...>
Sent: Friday, April 02, 2010 11:32 PM
Subject: [68HC12] Difference between S12 and S12X
>I have code written for a HCS12 Micro and was thinking about porting it
>over to a HCS12(X). It has interrupts, and it seems that the interrupts
>are handled differently. Is this true, or if the modules are the same
>between the 2 chips, will the code just port over and work the same.
>