NXP Semiconductors MPC5605BK, Reference Manual

Page: 111 / 964

Chapter 6 Clock Description
MPC5606BK Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 111
NOTE
The 32 KHz slow external crystal oscillator is by default always ON, but
can be configured OFF in standby by setting the OSCON bit.
6.5 Slow internal RC oscillator (SIRC) digital interface
6.5.1 Introduction
The SIRC digital interface controls the 128 kHz slow internal RC oscillator (SIRC). It holds control and
status registers accessible for application.
1
You can read this field, and you can write a value of 1 to it. Writing a 0 has no effect. A reset will also clear this bit.
2
You can write a value of “0” or “1” to this field. However, writing a “1” will clear this field, and writing “0” will have no
effect on the field value.
Table 6-5. SXOSC_CTL field descriptions
Field Description
OSCBYP Crystal Oscillator bypass.
This bit specifies whether the oscillator should be bypassed or not.
0 Oscillator output is used as root clock.
1 OSC32K_EXTAL is used as root clock.
EOCV End of Count Value.
This field specifies 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 × 512, the crystal oscillator clock interrupt (I_OSC)
request is generated. 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 is masked.
1 Crystal oscillator clock interrupt is enabled.
OSCDIV Crystal oscillator clock division factor.
This field specifies the crystal oscillator output clock division factor. The output clock is divided by
the factor 1.
I_OSC Crystal oscillator clock interrupt.
This field is set by hardware when OSCCNT counter reaches the count value EOCV × 512.
0 No oscillator clock interrupt occurred.
1 Oscillator clock interrupt pending.
S_OSC Crystal oscillator status.
0 Crystal oscillator output clock is not stable.
1 Crystal oscillator is providing a stable clock.
OSCON Crystal oscillator enable.
0 Crystal oscillator is switched off.
1 Crystal oscillator is switched on.