Clock, Reset, and Power Control (CRP)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
5-5
Preliminary
5.2.2.1
Clock Source Register (CRP_CLKSRC)
The CRP_CLKSRC contains:
•
enable bits for the 32 kHz IRC (32KIRC), the 32 kHz XOSC (32KOSC), and the main external
oscillator (XOSC)
•
the trim values for the 16 MHz IRC and 32 kHz IRC
Offset:
CR 0x0000
Access: User read/write
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
32KIRC
EN
XOSC
EN
0
32KOSC
EN
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
16
17
18
19
20
21
22
23
24
26
27
28
29
30
31
R
TRIM32IRC[0:7]
TRIMIRC[0:7]
W
Reset
1
0
1
1
1
1
1
1
0
0
0
1
1
1
1
1
These bits are only reset by power-on, VDD15 LVI, VDD33 LVI, VDDSYN LVI, VDD5 Low LVI, and VDD5 LVI.
2
These bits must not be changed.
3
These bits must remain set to a value of 1. Only the six least significant bits of TRIM32IRC are used.
Figure 5-2. Clock Source Register (CRP_CLKSRC)
Table 5-2. CRP_CLKSRC Field Descriptions
Field
Description
bits 0–11
Reserved.
IRC32KEN
32 kHz IRC Enable. The IRC32KEN bit enables the 32K IRC.
0 32 kHz IRC disabled
1 32 kHz IRC enabled
XOSCEN
External Oscillator Enable. The XOSCEN bit enables the external oscillator.
0 XOSC disabled.
1 XOSC enabled.
Note: During sleep and stop mode with XOSCEN=1, the XOSC will still actively drive an external crystal
but the XOSC clock to the system is disabled.
bit 14
Reserved.
OSC32KEN
32 kHz OSC Enable. The OSC32KEN bit enables the 32K oscillator.
0 32K OSC disabled
1 32K OSC enabled
Note: After enabling the 32K OSC, software needs to wait the required crystal startup/stabilization time
before making use of the 32K OSC.