Chapter 3 Memory Mapping Control (S12XMMCV4)
MC9S12XE-Family Reference Manual Rev. 1.19
Freescale Semiconductor
203
The reset value of 0xFD ensures that there is a linear RAM space available between addresses 0x1000 and
0x3FFF out of reset.
The fixed 4K page from 0x2000–0x2FFF of RAM is equivalent to page 254 (page number 0xFE).
The fixed 4K page from 0x3000–0x3FFF of RAM is equivalent to page 255 (page number 0xFF).
3.3.2.8
EEPROM Page Index Register (EPAGE)
Read: Anytime
Write: Anytime
These eight index bits are used to page 1 KByte blocks into the EEPROM page window located in the local
(CPU or BDM) memory map from address 0x0800 to address 0x0BFF (see
accessing up to 256 KByte of EEPROM (in the Global map) within the 64 KByte Local map. The
EEPROM page index register is effectively used to construct paged EEPROM addresses in the Local map
format.
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
Table 3-14. 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.
Address: 0x0017
7
6
5
4
3
2
1
0
R
EP7
EP6
EP5
EP4
EP3
EP2
EP1
EP0
W
Reset
1
1
1
1
1
1
1
0
Figure 3-15. EEPROM Page Index Register (EPAGE)
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
S12XE
products
in
208
MAPBGA
packages