Programming Model

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ROM A Base/Size Register

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Address

 

 

 

 

 

 

 

 

 

 

 

 

 

 

$FEF80050

 

 

 

 

 

 

 

 

 

 

 

 

Bit

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Name

 

 

 

ROM A BASE

 

 

rom a 64

rom a siz0

 

rom a siz1

rom a siz2

 

 

 

 

 

 

 

 

0

0

0

0

0

 

rom a rv

 

rom a en

 

rom a we

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Operation

 

 

 

READ/WRITE

 

 

R

R/W

 

R/W

R/W

 

READ ZERO

 

R

R

R

R

R

R/W

R/W

R/W

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

 

 

 

 

$FF0 PL

 

 

V

0

 

0

0

 

 

 

 

 

 

 

 

X

X

X

X

X

V

0

0

 

 

 

 

 

 

 

 

 

 

 

 

 

P

PL

 

PL

PL

 

 

 

X

 

 

 

 

 

 

P

PL

PL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ROM A BASE

These control bits define the base address for ROM/Flash Block A. ROM A BASE bits 0-11 correspond to PowerPC 60x address bits 0 - 11 respectively. For larger ROM/Flash sizes, the lower significant bits of ROM A BASE are ignored. This means that the block’s base address will always appear at an even multiple of its size. ROM A BASE is initialized to $FF0 at power-up or local bus reset.

Note that in addition to the programmed address, the first

1Mbyte of Block A also appears at $FFF00000 -

$FFFFFFFF if the rom_a_rv bit is set and the rom_b_rv bit is cleared.

Also note that the combination of ROM_A_BASE and rom_a_siz should never be programmed such that ROM/Flash Block A responds at the same address as the CSR, DRAM, External Register set, or any other slave on the PowerPC bus.

rom_a_64

rom_a_64 indicates the width of the ROM/Flash device(s) being used for Block A. When rom_a_64 is cleared, Block A is 16 bits wide, where each Falcon interfaces to 8 bits. When rom_a_64 is set, Block A is 64

3

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

3-45

Page 207
Image 207
Motorola MVME2300 Series manual ROM a Base, 1Mbyte of Block a also appears at $FFF00000