jsr changing registers in 68hc11?

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Hi All, I hope this is the right forum, I have a 68hc11
microcontroller, and im using BR to debug my buggy code (it has the
Buffalo monitor)
The gist of it is: I load numbers into registers and then jump to a
subroutine, i check the numbers before and after the jump, but they
have changed- any clues to what is happening?

Re: jsr changing registers in 68hc11?

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Is an interrupt occuring?

When you say "registers", do you mean MCU registers or I/O control

Buffalo is not a very good way to debug since it is invasive. You
might consider the 9s12 devices at some point because of their
superior BDM debugging.


Re: jsr changing registers in 68hc11?
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Hi Eric,
Thanks for responding!
by registers, I mean MCU registers, Reg X and Reg B.
Im using Buffalo, could the buffalo BR command be a cause?- i'm using
that to halt things to look at the registers.
I thought for a while I might have been using direct addressing by
accident instead of load immediate, but the check before the jump
subroutine command shows the number I want, but the check immediately
after the jump shows a
change! It is weird, the code works when loaded into ram, but I needed
it put in EEPROM, so I changed address labels around to suit etc....
and partial operation occurs, but not quite what I want, and it seems
to be at this jump point, that things are going amiss.

Re: jsr changing registers in 68hc11?
BWAHHHH!!  He he he found it- it's NOT changing the registers at
The same routine is called for earlier in the initialisation setup- so
when the break point exited,
I was looking at *those* values!  It pays to have a nights sleep on
the matter!
Thanks Eric for your time!

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