Programming Model

rom_b_64 matches the inverse of the value that was on the CKD3 pin at power-up reset. It cannot be changed by software.

rom b siz The rom b siz control bits are the size of ROM/Flash for block B. They are encoded as shown in Table 3-17.

Table 3-17. ROM Block B Size Encoding

rom b siz

Block Size

 

 

%000

1MB

 

 

%001

2MB

 

 

%010

4MB

 

 

%011

8MB

 

 

%100

16MB

 

 

%101

32MB

 

 

%110

64MB

 

 

%111

Reserved

 

 

rom_b_rv rom_b_rv and rom_a_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 Table 3-15.

rom_b_rv is initialized at power-up reset to match the inverse of the value on the CKD1 pin.

rom b en 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.

rom b we When rom b we is set, writes to block B ROM/Flash are enabled. When rom b we is cleared they are disabled. Refer back to Table 3-16for more details.

3

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Motorola MVME2300 Series manual ROM Block B Size Encoding, Rom b siz Block Size