zheng xuguang

problem of 9s12dp512 memory map?

Discussion created by zheng xuguang on Jan 17, 2009
Latest reply on Jan 17, 2009 by kef
hi all
    dp512 has the following on chip resource:  1K register; 4K eeprom; 14K ram; 512K flash; where two 16K unpaged flash is located at $4000 ~ $7fff and $c000 ~ $ffff. and the reset address space for register is $0000 ~ $03ff ; eeprom is $0000 ~ $0fff ; ram $0800 ~ $3fff. priority is register > ram > eeprom > flash.
    so after reset the available space for register is 1K($0000~$3ff) ; ram 14K ($800 ~ $3fff) ; eeprom 1K ($400 ~ $7ff), but i want to fully use of 4K eeprom and 14K ram , so i have to remap the memory map of eeprom and ram space.
    ram space  extended to  next 16K address space ($4000 ~ $7fff) , according to the priority of on chip resource, the unpaged flash block ( $4000 ~ $7fff ) is overlapped.
    my question is: if  the unpaged flash block ( $4000 ~ $7fff ) is overlapped, does that mean i can not place any application code to that area? if it is right, is there any method that can use the overlapped flash areas?