Chapter 4 Memory Protection Unit (S12XMPUV1)
MC9S12XE-Family Reference Manual , Rev. 1.19
234
Freescale Semiconductor
4.3.1.6
MPU Descriptor Register 0 (MPUDESC0)
Figure 4-8. MPU Descriptor Register 0 (MPUDESC0)
Read: Anytime
Write: Anytime
Table 4-8. MPUDESC0 Field Descriptions
A descriptor can be configured as valid for more than one bus-master at the same time by setting multiple
Master select bits to one. Setting all Master select bits of a descriptor to zero disables the descriptor.
4.3.1.7
MPU Descriptor Register 1 (MPUDESC1)
Figure 4-9. MPU Descriptor Register 1 (MPUDESC1)
Read: Anytime
Write: Anytime
Address: Module Base + 0x0006
7
6
5
4
3
2
1
0
R
MSTR0
MSTR1
MSTR2
MSTR3
LOW_ADDR[22:19]
W
Reset
1
(1)
1. initialized as set for descriptor 0 only, cleared for all others
1
1
1
(2)
2. initialized as set for descriptor 0 only, if MSTR3 is implemented on the device
0
0
0
0
Field
Description
7
MSTR0
Master 0 select bit
— If this bit is set the descriptor is valid for bus master 0 (CPU in supervisor state).
6
MSTR1
Master 1 select bit
— If this bit is set the descriptor is valid for bus master 1 (CPU in user state).
5
MSTR2
Master 2 select bit
— If this bit is set the descriptor is valid for bus master 2 (XGATE).
4
MSTR3
Master 3 select bit
— If this bit is set the descriptor is valid for bus master 3.
3–0
LOW_ADDR[
22:19]
Memory range lower boundary address bits
— The LOW_ADDR[22:19] bits represent bits [22:19] of the
global memory address that is used as the lower boundary for the described memory range.
Address: Module Base + 0x0007
7
6
5
4
3
2
1
0
R
LOW_ADDR[18:11]
W
Reset
0
0
0
0
0
0
0
0
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