3

Falcon ECC Memory Controller Chip Set

 

 

 

 

 

 

 

 

 

 

 

The output of the chip prescale counter is used by the

 

 

 

 

 

 

 

 

 

 

 

 

refresher/scrubber and the 32-bit counter. After power-up,

 

 

 

 

 

 

 

 

 

 

 

this register is initialized to $42 (for 66MHz).

 

 

 

 

 

 

 

 

 

 

por

 

 

 

 

 

por is set by the occurrence of power-up reset. It is cleared

 

 

 

 

 

 

 

 

 

 

 

by writing a 1 to it. Writing a 0 to it has no effect.

 

 

 

 

ECC Control Register

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Address

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

$FEF80028

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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

0

0

0

0

0

refdis

 

rwcb

 

derc

0

0

0

0

scien

 

tien

sien

mien

 

 

 

 

 

 

 

 

0

0

0

 

0

0

0

0

 

mcken

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Operation

R

R

R

R

R

R/W

 

R/W

 

R/W

R

R

R

R

R/W

 

R/W

R/W

R/W

 

READ ZERO

R

R

R

 

R

R

R

R

 

R/W

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

X

X

X

X

X

0

0

1

X

X

X

X

0

0

0

0

 

 

 

 

 

 

 

 

X

X

X

X

X

X

X

 

0

 

 

 

 

 

 

PL

 

PL

 

PL

 

 

 

 

PL

 

PL

PL

PL

 

 

 

X

 

 

 

 

 

 

 

 

 

PL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

refdis

 

 

 

When set, refdis causes the refresher and all of its

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

associated counters and state machines to be cleared and

 

 

 

 

 

 

 

 

 

 

 

maintained that way until refdis is removed (cleared). If a

 

 

 

 

 

 

 

 

 

 

 

refresh cycle is in process when refdis is updated by a

 

 

 

 

 

 

 

 

 

 

 

 

write to this register, the update does not take effect until

 

 

 

 

 

 

 

 

 

 

 

the refresh cycle has completed. This prevents the

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

generation of illegal cycles to the DRAM when refdis is

 

 

 

 

 

 

 

 

 

 

 

updated.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

rwcb

 

 

 

rwcb, when set, causes reads and writes to DRAM from

 

 

 

 

 

 

 

 

 

 

 

the PowerPC 60x bus to access check-bit data rather than

normal data. The data path used for this mode is DH24-31 for check-bit data controlled by the upper Falcon, and DL24-31 for check-bit data controlled by the lower Falcon. Each 8-bit check-bit location services 64 bits of normal data. The 64 bits of data are all within the same Falcon. Each Falcon provides every other 32 bits of data in the normal mode. The following figure shows the relationship between normal data and check-bit data.

3-36

Computer Group Literature Center Web Site

Page 198
Image 198
Motorola MVME2300 Series manual ECC Control Register, Refdis, Rwcb, Read Zero