Chapter 3 Memory Mapping Control (S12XMMCV4)
MC9S12XE-Family Reference Manual , Rev. 1.19
214
Freescale Semiconductor
3.4.2.5
Memory Configuration
Two bits in the MMCCTL1 register (ROMHM, RAMHM) configure the mapping of the local address
(0x4000-0x7FFF) in the global memory map.
ROMHM, RAMHM are write once in normal and emulation modes and anytime in special modes.
Three areas are identified (See
•
Program FLASH (0x7F_4000-0x7F_7FFF) when ROMHM = 0.
•
External Space (0x14_4000-0x14_7FFF) when ROMHM = 1 and RAMHM = 0.
•
XSRAM Space (0x0F_C000-0x0F_FFFF) when ROMHM = 1 and RAMHM = 1.
shows the translation from the local memory map to the global memory map taking in
consideration the different configurations of ROMHM and RAMHM.
describes the application note of the RAM configuration and its dedicated global address.
Table 3-19. ROMHM and RAMHM Address Location
Local Address
ROMHM
RAMHM
Global Address
Location
0x4000 - 0x7FFF
0
X
0x7F_4000 - 0x7F_7FFF
Internal Flash
1
0
0x14_4000 - 0x14_7FFF
External Space
1
1
0x0F_C000 - 0x0F_FFFF
Bottom of the Implemented RAM
0x2000 - 0x3FFF
0x0F_A000 - 0x0F_BFFF
Fixed up to 8K RAM
0x2000 - 0x3FFF
1
0
0x0F_E000 - 0x0F_FFFF
Fixed up to 8K RAM
Table 3-20. RAM Configuration
phase
RPAGE
ROMHM
RAMHM
RAM AREA
Global Address
After reset
RPAGE = 0xFD
(Reset value)
0
0
12 Kilobytes
0x0F_D000 - 0x0F_FFFF
During setup
RPAGE = 0xFD
(Reset value)
1
1
24 Kilobytes
0x0F_A000 - 0x0F_FFFF
Normal Operation
(0x00 <= RPAGE <= 0xF9)
1
1
28 Kilobytes
0x00_0000 - 0x0F_9FFF
(0xFA <= RPAGE <= 0xFF)
1
1
24 Kilobytes
0x0F_A000 - 0x0F_FFFF
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