Chapter 23 Memory Mapping Control (S12XMMCV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
894 Freescale Semiconductor
23.3.2.7 EEPROM Page Index Register (EPAGE)
Read: Anytime
Write: Anytime
The EEPROM page index register allows accessing up to 256 Kbyte of EEPROM in the global memory
map by using the eight page index bits to page 1 Kbyte blocks into the EEPROM page window located in
the local CPU memory map from address $0800 to address $0BFF (see Figure 1-14).
CAUTION
XGATE write access to this register during an CPU access which makes use
of this register could lead to unexpected results.
Figure 23-14. EPAGE Address Mapping
The reset value of $FE ensures that there is a linear EEPROM space available between addresses $0800
and $0FFF out of reset.
The fixed 1K page $0C00–$0FFF of EEPROM is equivalent to page 255 (page number $FF).
Address: 0x0017
76543210
REP7 EP6 EP5 EP4 EP3 EP2 EP1 EP0
W
Reset 11111110
Figure 23-13. EEPROM Page Index Register (EPAGE)
Table 23-12. EPAGE Field Descriptions
Field Description
7–0
EP[7:0]
EEPROM Page Index Bits 7–0 — These page index bits are used to select which of the 256 EEPROM array
pages is to be accessed in the EEPROM Page Window.
Bit16 Bit0
Bit9
Address [9:0]
EPAGE Register [7:0]
Global Address [22:0]
Bit10
Bit17
00 100
Address: CPU Local Address
or BDM Local Address