User manual

Chapter 23 Memory Mapping Control (S12XMMCV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
Freescale Semiconductor 893
Figure 23-12. RPAGE Address Mapping
NOTE
Because RAM page 0 has the same global address as the register space, it is
possible to write to registers through the RAM space when RPAGE = $00.
The reset value of $FD ensures that there is a linear RAM space available between addresses $1000 and
$3FFF out of reset.
The fixed 4K page from $2000–$2FFF of RAM is equivalent to page 254 (page number $FE).
The fixed 4K page from $3000–$3FFF of RAM is equivalent to page 255 (page number $FF).
Table 23-11. RPAGE Field Descriptions
Field Description
7–0
RP[7:0]
RAM Page Index Bits 7–0 — These page index bits are used to select which of the 256 RAM array pages is to
be accessed in the RAM Page Window.
Bit18
Bit0
Bit11
0
Address [11:0]
RPAGE Register [7:0]
Global Address [22:0]
Bit12
Bit19
0
Address: CPU Local Address
or BDM Local Address
0