Chapter 4 Clock Description
MPC5602P Microcontroller Reference Manual, Rev. 4
88
Freescale Semiconductor
4.7.2
Register description
Table 4-3. OSC_CTL memory map
Offset from
OSC_CTL_BASE
(0xC3FE_0000)
Register
Access
Reset value
Location
0x0000
OSC_CTL—Oscillator control register
R/W
0x0080_0000
0x0004–0x000F
Reserved
Address: 0xC3FE_0000
(Base + 0x0000)
Access: Supervisor read/write; User read-only
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R OSC
BYP
0
0
0
0
0
0
0
EOCV[7:0]
W
Reset
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R
M_
OSC
0
0
0
0
0
0
0
I_
OSC
0
0
0
0
0
0
0
W
w1c
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 4-5. Crystal Oscillator Control register (OSC_CTL)
Table 4-4. OSC_CTL field descriptions
Field
Description
OSCBYP
Crystal Oscillator bypass
This bit specifies whether the oscillator should be bypassed or not. Software can only set this bit.
System reset is needed to reset this bit.
0: Oscillator output is used as root clock.
1: EXTAL is used as root clock.
EOCV[7:0] End of Count Value
These bits specify the end of count value to be used for comparison by the oscillator stabilization
counter OSCCNT after reset or whenever it is switched on from the off state. This counting period
ensures that external oscillator clock signal is stable before it can be selected by the system. When
oscillator counter reaches the value EOCV[7:0]*512, oscillator available interrupt request is generated.
The reset value of this field depends on the device specification. The OSCCNT counter will be kept
under reset if oscillator bypass mode is selected.
M_OSC
Crystal oscillator clock interrupt mask
0: Crystal oscillator clock interrupt masked
1: Crystal oscillator clock interrupt enabled
I_OSC
Crystal oscillator clock interrupt
This bit is set by hardware when OSCCNT counter reaches the count value EOCV[7:0]*512. It is
cleared by software by writing 1.
0: No oscillator clock interrupt occurred
1: Oscillator clock interrupt pending