System Integration Unit (SIU)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
6-35
Preliminary
6.3.2.21
Compare A High Register (SIU_CMPAH)
The SIU_CMPAH register holds the 32-bit value that is compared against the value in the SIU_CMPBH
register. The CMPAH field is read/write and reset by the asynchronous reset signal.
Offset:
SI 0x0984
Access: User read-only
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
EBDF
W
Reset
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
1
Figure 6-23. External Clock Control Register (SIU_ECCR)
Table 6-25. SIU_ECCR Field Descriptions
Field
Description
bits 0–29
Reserved.
Note: Reserved bits 16–24 and 28 are writeable, but writing to these bits has no effect other than to
update the value of the register. For future compatibility, these bits should be written to zeros.
EBDF
External Bus Division Factor. Specifies frequency ratio between system clock and external clock,
CLKOUT. The EBDF field must not be changed during an external bus access or while an access is
pending. The CLKOUT frequency is divided from the system clock frequency according to the
descriptions below.
00 Divide by 1
01 Divide by 2
10 Reserved
11 Divide by 4
Note: The reset value of the EBDF field is divide-by-2.
Note: The EBDF field must not be modified while an external bus transaction is in progress.
Note: If EBDF is equal to 0x00 and SYSCLKDIV is not equal to 0x00, then the CLKOUT pin will not
have a nominal 50% duty cycle.