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Subject: 
Re: Watch Dog Timer on legOs
Newsgroups: 
lugnet.robotics
Date: 
Sat, 13 Mar 1999 23:00:31 GMT
Viewed: 
1080 times
  
Giovannoni, Brian <Brian_Giovannoni@NAI.com> wrote:
Anyone have any experience using Interrupts for the h8300? I want to add a
watch-dog time routine to legOs. I was hoping someone could nudge me in the
right direction?? I just need to understand how to access the system clock?

Not that I describe in great detail how to do exactly what you want to do,
but you probably want to take a look at:

http://graphics.stanford.edu/~kekoa/rcx/opcodes.html

A lot of the low-level RCX details are described there.

It sounds like you want to:

- read up on watchdog timers in the h8/300 manual
- store the address of your interrupt handler at fdbe, the interrupt vector
     for the watchdog timer
- figure out how to setup and enable the watchdog timer, making sure you
     don't create conflicts with the low-level internals of LegOS

There might be some asm issues to consider.  In particular, your interrupt
handler needs to make sure to save and restore the registers that gcc
expects to be able to overwrite.  I believe this means r0 through r3.
These are not saved by the ROM.

-Kekoa



Message is in Reply To:
  Watch Dog Timer on legOs
 
Anyone have any experience using Interrupts for the h8300? I want to add a watch-dog time routine to legOs. I was hoping someone could nudge me in the right direction?? I just need to understand how to access the system clock? Brian -- Did you check (...) (26 years ago, 13-Mar-99, to lugnet.robotics)

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