Programming Model

Base Address Register

These eight bits are combined with the two most significant bits in Register 7 (the next register) to form BAD31-BAD22, which defines the base address of the memory. For larger memory sizes, the lower significant bits are ignored.

The bit assignments for the Base Address register are:

ADR/SIZ

 

 

1st $FFF43014/2nd $FFF43114 (8-bits)

 

 

 

 

 

 

 

 

 

 

 

 

 

BIT

31

30

 

29

28

27

26

 

25

24

 

 

 

 

 

 

 

 

 

 

 

NAME

BAD31

BAD30

 

BAD29

BAD28

BAD27

BAD26

 

BAD25

BAD24

 

 

 

 

 

 

 

 

 

 

 

OPER

R/W

R/W

 

R/W

R/W

R/W

R/W

 

R/W

R/W

 

 

 

 

 

 

 

 

 

 

 

RESET

0 PLS

0 PLS

 

0 PLS

0 PLS

0 PLS

0 PLS

 

0 PLS

0 PLS

 

 

 

 

 

 

 

 

 

 

 

4

DRAM Control Register

The bit assignments for the DRAM Control register are:

ADR/SIZ

 

 

1st $FFF43018/2nd $FFF43118 (8-bits)

 

 

 

 

 

 

 

 

 

 

 

BIT

31

30

 

29

28

27

26

25

24

 

 

 

 

 

 

 

 

 

 

NAME

BAD23

BAD22

 

RWB5

RWB4

RWB3

NCEIEN

NCEBEN

RAMEN

 

 

 

 

 

 

 

 

 

 

OPER

R/W

R/W

 

R/W

R/W

R/W

R/W

R

R/W

 

 

 

 

 

 

 

 

 

 

RESET

0 PLS

0 PLS

 

0 PLS

0 PLS

0 PLS

0 PLS

0 PLS

0 PLS

 

 

 

 

 

 

 

 

 

 

RAMEN RAM Enable. This control bit is used to enable the local bus to perform read/write accesses to the memory. Accesses are enabled when this bit is set and are disabled when this bit is cleared. This bit should only be set after BAD31-BAD22 have been initialized.

http://www.motorola.com/computer/literature

4-15

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Image 263
Motorola MVME1X7P manual Base Address Register, Dram Control Register, Bit assignments for the Dram Control register are