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 Robotics / RCX / 2128
2127  |  2129
Subject: 
Port 5 Bit 2
Newsgroups: 
lugnet.robotics.rcx
Date: 
Fri, 27 Jun 2003 22:25:38 GMT
Viewed: 
2792 times
  
Hi,

While delving into the nitty gritty details of the RCX's power off
routine, which was discussed a *long* time ago in these threads:

http://news.lugnet.com/robotics/rcx/legos/?n=49&t=i&v=a
http://news.lugnet.com/robotics/rcx/legos/?n=50&t=i&v=a

(Note the very low message numbers... :)

I noticed that in addition to putting the RAM into low power
mode, port 5 bit 2 also cuts power to the 10K pull-up resistors
in the sensor ports.  This prevents sensors (both active and
passive) from drawing current while the RCX is off.  The bit
probably also turns off other non-essential circuitry.

Anyways, since I wasn't able to find any info about this here
or at RCX Internals, I thought I'd post it in case someone
down the road might find this little tidbit useful...

Also, to summarize the above threads, if you're gonna call sleep in
software standby mode (to power down the RCX), be sure that
the stack, IRQ1 handler, and the instruction to clear port 5 bit 2
are all in ROM or on-chip RAM.  Now I know.  :-)

Mark (still wondering about port 6 bit 3)



Message has 1 Reply:
  RE: Port 5 Bit 2
 
Mark, Good information. I was wondering what else got powered down by that bit. Once again, I think we need to take a moment to think about what life would be like without LUGNET. Just having those old archives to look through can help save a large (...) (21 years ago, 30-Jun-03, to lugnet.robotics.rcx)

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