Motorola MVME5100 用户手册
Programming Model
http://www.motorola.com/computer/literature
3-55
3
each half of the SMC interfaces to 32 bits. rom_a_64
matches the value that was on the RD2 pin at power-up
reset. It cannot be changed by software.
matches the value that was on the RD2 pin at power-up
reset. It cannot be changed by software.
rom a siz
The rom a siz control bits are the size of ROM/Flash for
Block A. They are encoded as shown in Table 3-11.
Block A. They are encoded as shown in Table 3-11.
rom_a_rv rom_a_rv and rom_b_rv determine which if either of
Blocks A and B is the source of reset vectors or any other
access in the range $FFF00000 - $FFFFFFFF as shown in
the table below.
access in the range $FFF00000 - $FFFFFFFF as shown in
the table below.
Table 3-11. ROM Block A Size Encoding
rom a siz
BLOCK
SIZE
%000
1MB
%001
2MB
%010
4MB
%011
8MB
%100
16MB
%101
32MB
%110
64MB
%111
Reserved
Table 3-12. rom_a_rv and rom_b_rv encoding
rom_a_rv
rom_b_rv
Result
0
0
Neither Block is the source of
reset vectors.
reset vectors.
0
1
Block B is the source of reset
vectors.
vectors.
1
0
Block A is the source of reset
vectors.
vectors.
1
1
Block B is the source of reset
vectors.
vectors.