Memory Map Problem

baumann1 · ‎2005-08-22

Posted on August 22, 2005 at 11:02

Memory Map Problem

baumann1 · ‎2011-05-17

Posted on May 17, 2011 at 12:08

Hi,

we used to use the PSD813 as program space and and EPROM in a socket as removable update-device.

Everything worked perfect. - ItÂ´s an 8051-arcitecture.

Now we use additionally for the first time the SRAM mapped in data space. During the update sequence we read from the EPROM, but now I will have to block or mask out the SRAM space.

Is it possible to do that by changing the PSD-registers?

Or what to do else??

please help!

Linus

jdaniel · ‎2011-05-17

Posted on May 17, 2011 at 12:08

Take a look at the definition of the ''VM'' register in the PSD data sheet. It controls what pins generate chip-selects for what pieces of internal PSD memory. You can use that to stop RD from accessing the SRAM.