68300

The address lines are active during all accesses as well as Read/write.  What is NOT active is the data bus during internal reads and writes.
 
Port E contains the bus control signals.  You really can't write anything meaningful to Port E if it is configured as bus control signals.  You can only perform meaningful reads and writes if the port is configured as I/O.  It the port E is configured as bus control signals, you can still read and write to the Port E Data Register and Port E Data Direction Register, but it will have no effect on the port.  However, if you do modifiy the Port E Data Register and Data Direction Register and then modify the Port E Pin Assignment register, the values previously written to the Data Register and the Data Direction Register will take effect immediately.
 
If you want to view the contents of the data bus during an internal access, you must turn on "show cycles".  However, this will slow the machine down.
 
Charlie

-----Original Message-----
From: howto68332 [mailto:sscomputers2@...]
Sent: Wednesday, April 09, 2003 2:36 PM
To: 68300@yahoogroups.com; 68300@yahoogroups.com; 68300@yahoogroups.com
Subject: [68300] Using addresslines during I/O port access


In the 68332 are either the address lines or the R/notW line active 
during access to 
the internal PortE data register when it is configured as an I/O 
port? 
( 
Or any of the internal ports for that matter? )





Yahoo! Groups Sponsor	
 <http://us.ard.yahoo.com/M=249982.3083889.4452939.1728375/D=egroupweb/S=1706554205:HM/A=1524963/R=0/*http://hits.411web.com/cgi-bin/autoredir?camp=556&lineid=3083889&prop=egroupweb&pos=HM> 	
  <http://us.adserver.yahoo.com/l?M=249982.3083889.4452939.1728375/D=egroupmail/S=:HM/A=1524963/rand=563174944> 	

---------------------------------------------------
To unsubscribe from this group, send an email to:
68300-unsubscribe@yahoogroups.com

To learn more about Motorola Microcontrollers, please visit
http://www.motorola.com/mcu <http://www.motorola.com/mcu> 



Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> . 




[Non-text portions of this message have been removed]