Re: ADDR []and DATA[] connections for 8 & 16 bit memory
alex shulman <[email protected]>
| Newsgroups | gmane.comp.hardware.motorola.microcontrollers |
|---|---|
| Message-ID | <[email protected]> |
Hi, You are correct for data bus. Addresses are more complex matter. For 8 bit memory you have to route address 31 to the memory device LSB address line and, for 16 bit configuration you have to route address 30 of the MCU to the memory lsb address line. Other lines should be routed accordingly. So to have 8/16 bit memory option on one board you'll need or a lot of jumpers or three memory placeholders - one for 8 bit option and two for 16 bit option. Regards Alex. --- murphynetuk <[email protected]> wrote: > Hi, > I want to layout my MPC555 board with the option of > either 1 or 2 8-bit > memory devices. With a single chip installed I would > access it as 8- > bit, with 2 chips I want to access them as a single > 16-bit device (by > approprate register entries). My question is how to > layout the ADDR[] > and DATA[] lines? I assume that DATA[0..7] would go > to the single chip > location and DATA[8..15] to the 2nd location. But > what about ADDR[]? > The reference manual is very unclear on this issue. > Regards, Ian > > > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ------------------------ Yahoo! Groups Sponsor --------------------~--> <font face=arial size=-1><a href="http://us.ard.yahoo.com/SIG=12h2l5p66/M=362131.6882499.7825260.1510227/D=groups/S=1706554205:TM/Y=YAHOO/EXP=1124313354/A=2889191/R=0/SIG=10r90krvo/*http://www.thebeehive.org ">Get Bzzzy! (real tools to help you find a job) Welcome to the Sweet Life -Â brought to you by One Economy</a>.</font> --------------------------------------------------------------------~-> ----------------------------------------------------------- To learn more about Freescale Microcontrollers, please visit http://www.freescale.com/mcu Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/MPC500/ <*> To unsubscribe from this group, send an email to: [email protected] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/