Infineon Technologies TC1784, Руководство пользователя

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TC1784
LMB External Bus Unit
User´s Manual 12-20 V1.1, 2011-05
EBUT13L-A, V1.16
The EBU uses the four region select outputs from the above scheme, in conjunction with
its own address decode logic, to react to LMB accesses as follows:
1.
Address is in the EBU register space:
An EBU register access is executed, and in case of a illegal register address, LMB
Error Acknowledge is retuned.
2. Address matches exactly one enabled external region:
The requested access is performed to external memory.
3. Address matches more than one enabled region (overlapping regions):
The requested access is performed using the parameters from the region with
highest priority. The region with the lowest region number x (region 0) has the highest
priority. The emulator region has lowest priority).
4. Address matches disabled region(s) or no address match:
The EBU returns a LMB Error Acknowledge.
When defining mirrored segments, the user is responsible for ensuring that there is no
collision. There is no checking mechanism in hardware that ensures that each segment
defined (either in BASE[31:28] or ALTSEG[11:8] or both) is exclusive. Therefore, the
user must ensure that each mapping from region 0 to 3 and the emulator region does not
interfere with any other; otherwise, only the mapping with the highest priority will take
effect.
1010
B
10 A[26:17] 128 Kbyte A[16:0]
1001
B
9 A[26:18] 256 Kbyte A[17:0]
1000
B
8 A[26:19] 512 Kbyte A[18:0]
0111
B
7 A[26:20] 1 Mbyte A[19:0]
0110
B
6 A[26:21] 2 Mbyte A[20:0]
0101
B
5 A[26:22] 4 Mbyte A[21:0]
0100
B
4 A[26:23] 8 Mbyte A[22:0]
0011
B
3 A[26:24] 16 Mbyte A[23:0]
0010
B
2 A[26:25] 32 Mbyte
1)
A[24:0]
0001
B
1 A[26] 64 Mbyte
1)
A[25:0]
0000
B
0 – 128 Mbyte
1)
A[26:0]
1) These region size selections do not affect the external address bus of the TC1784 because A24, A25,and A26
are not output at pins (only A[21:1] are available at TC1784 pins).
Table 12-13 EBU Address Regions Size and Start Address Relations (cont’d)
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