Reply by Tony Papadimitriou●June 24, 20042004-06-24
An infinite BRA loop is sometimes used after initialization to let some
interrupt take control periodically. It doesn't have to be non-maskable.
Often, the IDLE task in an RTOS is a BRA * loop.
----- Original Message -----
From: "Torgeir Veimo" <>
To: <>
Sent: Thursday, June 24, 2004 11:22 AM
Subject: Re: [m68HC11] reprogramming an OTP device
> Robert Mitchell wrote:
>
> > Have you considered $2000 - should branch to the next instruction,
i.e.
> > behave as a 2 byte NOP.
>
> Thanks, this was what I was looking for.
>
> Normally, only a reset or a nonmaskable interrupt can take regain
> control of the hc11 in these cases, right?
>
> --
> -Torgeir
Reply by Torgeir Veimo●June 24, 20042004-06-24
Robert Mitchell wrote:
> Have you considered $2000 - should branch to the
next instruction, i.e.
> behave as a 2 byte NOP.
Thanks, this was what I was looking for.
Normally, only a reset or a nonmaskable interrupt can take regain
control of the hc11 in these cases, right?
--
-Torgeir
Reply by Tony Papadimitriou●June 24, 20042004-06-24
Turn the $20FE to $2000 to BRA to the next opcode, in effect making this a
NOP.
----- Original Message -----
From: "Torgeir Veimo" <>
To: <>
Sent: Thursday, June 24, 2004 3:17 AM
Subject: [m68HC11] reprogramming an OTP device
> I have a legacy hc11 application in an 68hc711e9
with OTP ROM which has
> at one point an instruction that is
>
> (raw instruction bytes $20FE)
>
> loc BRA loc
>
> ie an infinite loop. What bytes can I reprogram these two bits to
> function as to avoid this loop? NOP is out of the question as it is $21.
> I can only turn bits to zero when (re)programming an OTP device, right?
>
> --
> -Torgeir
Reply by Robert Mitchell●June 23, 20042004-06-23
Have you considered $2000 - should branch to the next instruction, i.e.
behave as a 2 byte NOP.
On Thu, 2004-06-24 at 10:17, Torgeir Veimo wrote: > I have a legacy hc11 application in an 68hc711e9
with OTP ROM which has
> at one point an instruction that is
>
> (raw instruction bytes $20FE)
>
> loc BRA loc
>
> ie an infinite loop. What bytes can I reprogram these two bits to
> function as to avoid this loop? NOP is out of the question as it is $21.
> I can only turn bits to zero when (re)programming an OTP device, right? --
Bob Mitchell
PO Box 68 Phone (+61 2) 9449 4736
(21 Hudson Close) Fax (+61 2) 9449 1976
Turramurra, 2074 Mobile 0411554117
NSW, Australia Email
Reply by Torgeir Veimo●June 23, 20042004-06-23
I have a legacy hc11 application in an 68hc711e9 with OTP ROM which has
at one point an instruction that is
(raw instruction bytes $20FE)
loc BRA loc
ie an infinite loop. What bytes can I reprogram these two bits to
function as to avoid this loop? NOP is out of the question as it is $21.
I can only turn bits to zero when (re)programming an OTP device, right?