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MPU Segments
The main memory always consists of 32 pages, page 0 through page 31. The page size changes based
on the size of the available main memory on a device. For example, a 16KB device has a page size of
512B (16KB / 32), an 8KB device has a page size of 256B (8KB / 32) pages, and a 4KB device has a
page size of 128B (4KB / 32 ). The border segments, B1 and B2, can be set to align on any of these 32
pages. The MUSBx[4:0] bits are used to select the appropriate page for the respective borders.
The start address for each page can be computed as follows:
Page_Start
n
= Maximum Memory Address - Memory Size x (32 - n ) / 32 + 1, where n = 0 to 31
The end address for each page can be computed as follows:
Page_End
n
= Maximum Memory A Memory Size x (32 - n ) / 32, where n = 0 to 31
shows the results of these calculations for a 16KB, 8KB, and 4KB main memory devices.
Table 6-1. Page Addresses for 16KB, 8KB, and 4KB Main Memory
16KB Main Memory
8KB Main Memory
4KB Main Memory
Page
MUSBx[4:0]
Page_Start
Page_End
Page_Start
Page_End
Page_Start
Page_End
Address
Address
Address
Address
Address
Address
0
00h
C000h
C1FFh
E000h
E0FFh
F000h
F07Fh
1
01h
C200h
C3FFh
E100h
E1FFh
F080h
F0FFh
2
02h
C400h
C5FFh
E200h
E2FFh
F100h
F17Fh
3
03h
C600h
C7FFh
E300h
E3FFh
F180h
F1FFh
4
04h
C800h
C9FFh
E400h
E4FFh
F200h
F27Fh
5
05h
CA00h
CBFFh
E500h
E5FFh
F280h
F2FFh
6
06h
CC00h
CDFFh
E600h
E6FFh
F300h
F37Fh
7
07h
CE00h
CFFFh
E700h
E7FFh
F380h
F3FFh
8
08h
D000h
D1FFh
E800h
E8FFh
F400h
F47Fh
9
09h
D200h
D3FFh
E900h
E9FFh
F480h
F4FFh
10
0Ah
D400h
D5FFh
EA00h
EAFFh
F500h
F57Fh
11
0Bh
D600h
D7FFh
EB00h
EBFFh
F580h
F5FFh
12
0Ch
D800h
D9FFh
EC00h
ECFFh
F600h
F67Fh
13
0Dh
DA00h
DBFFh
ED00h
EDFFh
F680h
F6FFh
14
0Eh
DC00h
DDFFh
EE00h
EEFFh
F700h
F77Fh
15
0Fh
DE00h
DFFFh
EF00h
EFFFh
F780h
F7FFh
16
10h
E000h
E1FFh
F000h
F0FFh
F800h
F87Fh
17
11h
E200h
E3FFh
F100h
F1FFh
F880h
F8FFh
18
12h
E400h
E5FFh
F200h
F2FFh
F900h
F97Fh
19
13h
E600h
E7FFh
F300h
F3FFh
F980h
F9FFh
20
14h
E800h
E9FFh
F400h
F4FFh
FA00h
FA7Fh
21
15h
EA00h
EBFFh
F500h
F5FFh
FA80h
FAFFh
22
16h
EC00h
EDFFh
F600h
F6FFh
FB00h
FB7Fh
23
17h
EE00h
EFFFh
F700h
F7FFh
FB80h
FBFFh
24
18h
F000h
F1FFh
F800h
F8FFh
FC00h
FC7Fh
25
19h
F200h
F3FFh
F900h
F9FFh
FC80h
FCFFh
26
1Ah
F400h
F5FFh
FA00h
FAFFh
FD00h
FD7Fh
27
1Bh
F600h
F7FFh
FB00h
FBFFh
FD80h
FDFFh
28
1Ch
F800h
F9FFh
FC00h
FCFFh
FE00h
FE7Fh
29
1Dh
FA00h
FBFFh
FD00h
FDFFh
FE80h
FEFFh
30
1Eh
FC00h
FDFFh
FE00h
FEFFh
FF00h
FF7Fh
31
1Fh
FE00h
FFFFh
FF00h
FFFFh
FF80h
FFFFh
254
Memory Protection Unit (MPU)
SLAU272C – May 2011 – Revised November 2013
Copyright © 2011–2013, Texas Instruments Incorporated