Table 3-14. Rom Block B Size Encoding - Motorola MVME5100 Programmer's Reference Manual

rom_b_64 rom_b_64 indicates the width of ROM/Flash
rom b siz The rom b siz control bits are the size of ROM/Flash for

Table 3-14. ROM Block B Size Encoding

rom_b_rv rom_b_rv and rom_a_rv determine which if either of
rom b en
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device/devices being used for Block B. When rom_b_64
is cleared, Block B is 16 bits wide, where each half of the
SMC interfaces to 8 bits. When rom_b_64 is set, Block B
is 64 bits wide, where each half of the SMC interfaces to
32 bits. rom_b_64 matches the value that was on the RD3
pin at power-up reset. It cannot be changed by software.
Block B. They are encoded as shown in
BLOCK
rom b siz
SIZE
%000 1MB
%001 2MB
%010 4MB
%011 8MB
%100 16MB
%101 32MB
%110 64MB
%111 Reserved
Blocks A and B is the source of reset vectors or any other
access in the range $FFF00000 - $FFFFFFFF as shown in
Table 3-12.
rom_b_rv is initialized at power-up reset to match the
value on the RD1 pin.
When rom b en is set, accesses to Block B ROM/Flash in
the address range selected by ROM B BASE are enabled.
When rom b en is cleared they are disabled.
Programming Model
Table 3-14.
3-57
3