Programming Model
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1-17
1
The following sub-sections describe these system registers in detail.
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 MTX series, this field returns a value
of $FB.
SYSCLK System Clock Speed. This field relays the system clock speed
and the PCI clock speed information as follows:
SYSXC System External Cache Size. This field reflects size of the look-
aside cache on the system bus.
Register
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
Operation
READ ONLY
Reset
$FB
X
X
X
X
$F
$F
SYSCLK Value
System Clock Speed
PCI Clock Speed
0b0000 to 0b1100
Reserved
Reserved
0b1101
50 MHz
25 MHz
0b1110
60 MHz
30 MHz
0b1111
66.66 MHz
33.33 MHz