Programming Model

System Configuration Register (SYSCR)

The states of the RD[0:31] DRAM data pins, which have weak internal pull-ups, are latched by the upper Falcon chip at a rising edge of the power- up reset and stored in this System Configuration register to provide some information about the system. Configuration is accomplished with external pull-down resistors. This 32-bit read-only register is defined as follows:

REG

 

 

 

 

 

 

 

 

 

System Configuration Register - $FEF80400

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FIELD

 

 

 

 

SYSID

 

 

 

SYSCLK

SYSXC

 

P0STAT

P1STAT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OPER

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Read

Only

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RESET

 

 

 

 

$FD

 

 

 

 

1111

 

 

1111

 

 

 

0111

 

 

1111

 

 

 

1

1

 

$F

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SYSID System Identification. This field specifies the type of the overall system configuration so that the software may appropriately handle any software visible differences. For the MVME2300 series, this field returns a value of $FD.

SYSCLK System Clock Speed. This field relays the system clock speed and the PCI clock speed information as follows:

SYSCLK Value

System Clock Speed

PCI Clock Speed

 

 

 

0B0000 to 0B1100

Reserved

Reserved

 

 

 

0B1101

50MHz

25MHz

 

 

 

0B1110

60MHz

30MHz

 

 

 

0B1111

66.66MHz

33.33MHz

 

 

 

1

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Motorola MVME2300 Series manual System Configuration Register Syscr, System Configuration Register $FEF80400, $Fd