i have a problem with memory mapping. For some reason ,I want to remap the register address space: 0x0000-0x3FFF, ram address space：0x0400-0x37FF, and eeprom：0x3800-0x3FFF. I use mc9s12dp512, P&E USB multilink interface tool. The process as follows.
1. modify the prm files ,
/* RAM */
RAM = READ_WRITE 0x0400 TO 0x37FF;
/* EPROM */
EEPROM = READ_ONLY 0x3800 TO 0x3FFF;
2. in the start12.c file , join these commands :
INITRG = 0;
INITRM = 0;
INITEE = 0x31;
3. then in the main.c file ,define a globle const variable
const volatile unsigned char tst1 @ 0x3c00 = 0x0a;
problem is when run into the main() function, in my opinion, the tst1 should equal 0x0a, but actually , tst1 = 0xFF. And the address content is also 0xff through memory window.
thanks for help !
I think you have to check the following two conditions thoroughly ...
1. You have initialized both the registers "INITRG" and "INITRM" to the same value of zero in start12.c file. That means, you are telling the device to allocate the same memory for MCU Registers and for RAM.
2. I think you can not allign the RAM with start address of "0x0400" and EEPROM with "0x3800" in your prm file.
I suggest you to check the freescale application note AN2881.pdf which is attached with this post to properly modify your memory mapping.