Freescale Semiconductor ColdFire MCF52210 - Manual (Page 109)

Clock Module
MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 6-15
6.7.1.9 Real-Time Clock Control Register (RTCCR)
The RTCCR is used to configure the RTC oscillator.
Table 6-13. OCLR Field Descriptions
Field Description
7
OSCEN
External Oscillator Enable bit. This bit enables the crystal oscillator in external crystal or external oscillator
mode.
0 External oscillator is disabled.
1 External oscillator is enabled.
Note: When switching the clock source to the external oscillator, this bit should be set before
CCLR[OSCSEL] is cleared.
6
REFS
Reference Source bit. This bit configures the external oscillator for operation with an external crystal or
external oscillator.
0 External oscillator is running in external oscillator mode.
1 External oscillator is running in external crystal mode.
5
LPEN
Low-Power Enable bit. This bit configures the external oscillator to run in low-power mode when using an
external crystal.
0 External oscillator runs in normal-power mode.
1 External oscillator runs in low-power mode.
4
RANGE
Range bit. This bit configures the external oscillator to run with different frequency crystals.
0 Support external crystal of 32 kHz.
1 Support external crystal in the range of 1 MHz to 16 MHz.
3–0 Reserved, should be cleared.
IPSBAR
Offset: 0x12_0012 (RTCCR)
Access: Supervisor read/write
7 6 5 4 3 2 1 0
R — — —
OSCEN KHZEN REFS LPEN RTCSEL
W
Reset: 0 0 0 0 0 0 0 0
Figure 6-10. Real-Time Clock Control Register (RTCCR)
Table 6-14. RTCCR Field Descriptions
Field Description
7–5 Reserved, should be cleared.
4
OSCEN
RTC Oscillator Enable bit. This bit enables the RTC oscillator.
0 RTC oscillator is disabled.
1 RTC oscillator is enabled.
3
KHZEN
The KHZEN bit selects the operating frequency range of the oscillator
0 Oscillator operates in the kHz range.
1 Oscillator operates in the MHz range.