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Subject: 
FW: H8300 Stack and SLEEP
Newsgroups: 
lugnet.robotics.rcx.legos, lugnet.robotics, lugnet.robotics.rcx.pbforth
Date: 
Mon, 15 Mar 1999 15:42:32 GMT
Viewed: 
295 times
  
this is important news. Which sleep mode does this apply to, software
standby, hardware sleep or all of them?

Markus.

Markus, (and anyone else listening)

I think it applies to the RCX power_shutdown() function as described in
Kekoa's reference. The key is that this function puts the external RAM
into low-power mode.

If you are not calling power_shutdown() or you are not putting the
external RAM into low-power mode, then it's not an issue.

Here's what I exchanged with Kekoa over the weekend:

I think the following code provides a clue as to what is going on,
but right now I'm not willing to open up my RCX.

2a76:   7f ba 70 20    bset  #0x2,@0xba:8
2a7a:   01 80          sleep
2a7c:   7f ba 72 20    bclr  #0x2,@0xba:8

I'll bet that the external RAM chip enable is taken HIGH before
sleep, which puts the RAM into low power mode, and then taken
LOW after sleep returns. The processor keeps its internal RAM
alive, and puts the external RAM into low power mode.

I was assuming that the external RAM (where my stack is)
would be preserved and available, and obviously this is not the case.

Hope this helps...

Cheers,

Ralph Hempel - P.Eng

--------------------------------------------------------
Check out pbFORTH for LEGO Mindstorms at:
<http://www.bmts.com/~rhempel/lego/pbFORTH/default.html>
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Reply to:      rhempel at bmts dot com
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Message has 1 Reply:
  Re: FW: H8300 Stack and SLEEP
 
(...) To be more precise, it applies to sleep mode and software standby mode as long as you set port 5 bit 2 to high before activating either mode. It does not apply to hardware standby mode, since that does not save registers or end with an (...) (26 years ago, 16-Mar-99, to lugnet.robotics.rcx.legos, lugnet.robotics, lugnet.robotics.rcx.pbforth)

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