TC1784
LMB External Bus Unit
User´s Manual
12-19
V1.1, 2011-05
EBUT13L-A, V1.16
3. The most significant four bits of the LMB address (“main” segment address) are
compared to the most significant four bits of the BASE bit field. The result of the
comparison (1 if equal, otherwise 0) is fed to the OR gate.
4. The OR gate combines the result of the “main” and “alternate” segment comparisons
generates a 1 if the LMB address is in the selected segment(s) for the region,
otherwise it generates 0. The output of the OR gate is fed to the final AND gate.
5. Bit 27 of the LMB address is (unconditionally) compared with bit 15 of the BASE bit
field. The result of the comparison (1 if equal, otherwise 0) is fed to the final AND
gate.
6. The appropriate number of LMB address bits from bit 26 downwards is compared
with the corresponding bits from bit field BASE bit 14 downwards. The number of bits
used for the comparison is controlled by the MASK bit field. The result of the
comparison (1 if the appropriate bits are equal, otherwise 0) is fed to the final AND
gate.
7. The NAND gate delivers a 0 if a write is performed to a read-only region
(WRPROT=1), and prevents the region from being selected. The output of the NAND
gate is fed to the final AND gate.
8. The final AND gate delivers a 1 if a match occurs at the address comparison, and the
region x is enabled by REGENAB = 1, and the access is not a write access when the
region is defined as read-only access.
This address decoding scheme has the following effects:
•
The smallest possible address region is 2
12
bytes (4 Kbyte)
•
The largest possible address region is 2
27
bytes (128 Mbyte)
•
The start address of a region depends on the size of the region. It must be at an
address that is a multiple of the size of a region; for example, the smallest region can
be placed on any 4-Kbyte boundary, while the largest region can be placed on
8-Mbyte boundaries only.
shows the possible region sizes and start granularity, as determined by the
programming of the MASK bit field. The range of the offset address within such a region
is also given.
Table 12-13 EBU Address Regions Size and Start Address Relations
MASK
No. of Address
Bits compared
to BASE[26:12]
Range of Address
Bits compared to
BASE[26:12]
Region Size and
Start Address
Granularity
Range of Offset
Address Bits
within Region
1111
B
15
A[26:12]
4 Kbyte
A[11:0]
1110
B
14
A[26:13]
8 Kbyte
A[12:0]
1101
B
13
A[26:14]
16 Kbyte
A[13:0]
1100
B
12
A[26:15]
32 Kbyte
A[14:0]
1011
B
11
A[26:16]
64 Kbyte
A[15:0]
Содержание TC1784
Страница 1: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Страница 3: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Страница 950: ...TC1784 Direct Memory Access Controller DMA User s Manual 11 132 V1 1 2011 05 DMA V3 03 ...
Страница 1949: ...TC1784 General Purpose Timer Array GPTA v5 User s Manual 21 297 V1 1 2011 05 GPTA v5 V1 14 ...
Страница 2350: ...w w w i n f i n e o n c o m Published by Infineon Technologies AG Doc_Number ...