System configuration register (syscr), System configuration register (syscr) -25 – Motorola MVME2300 Series User Manual
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Programming Model
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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:
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:
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
SYSCLK Value
System Clock Speed
PCI Clock Speed
0B0000 to 0B1100
Reserved
Reserved
0B1101
50MHz
25MHz
0B1110
60MHz
30MHz
0B1111
66.66MHz
33.33MHz