Information

MCG_C7 field descriptions
Field Description
7–1
Reserved
This read-only field is reserved and always has the value zero.
0
OSCSEL
MCG OSC Clock Select
Selects the MCG FLL external reference clock
0 Selects System Oscillator (OSCCLK).
1 Selects 32 kHz RTC Oscillator.
24.3.12 MCG Control 8 Register (MCG_C8)
Address: MCG_C8 is 4006_4000h base + Dh offset = 4006_400Dh
Bit 7 6 5 4 3 2 1 0
Read
LOCRE1 LOLRE CME1
0 LOCS1
Write
Reset
1 0 0 0 0 0 0 0
MCG_C8 field descriptions
Field Description
7
LOCRE1
Loss of Clock Reset Enable
Determines if a interrupt or a reset request is made following a loss of RTC external reference clock. The
LOCRE1 only has an affect when CME1 is set.
0 Interrupt request is generated on a loss of RTC external reference clock.
1 Generate a reset request on a loss of RTC external reference clock
6
LOLRE
0 Interrupt request is generated on a PLL loss of lock indication. The PLL loss of lock interrupt enable
bit must also be set to generate the interrupt request.
1 Generate a reset request on a PLL loss of lock indication.
5
CME1
Clock Monitor Enable1
Enables the loss of clock monitoring circuit for the output of the RTC external reference clock. The
LOCRE1 bit will determine whether an interrupt or a reset request is generated following a loss of RTC
clock indication. The CME1 bit should be set to a logic 1 when the MCG is in an operational mode that
uses the RTC as its external reference clock or if the RTC is operational. CME1 bit must be set to a logic
0 before the MCG enters any Stop mode. Otherwise, a reset request may occur when in Stop mode.
CME1 should also be set to a logic 0 before entering VLPR or VLPW power modes.
0 External clock monitor is disabled for RTC clock.
1 External clock monitor is enabled for RTC clock.
4–1
Reserved
This read-only field is reserved and always has the value zero.
0
LOCS1
RTC Loss of Clock Status
This bit indicates when a loss of clock has occurred. This bit is cleared by writing a logic 1 to it when set.
Table continues on the next page...
Chapter 24 Multipurpose Clock Generator (MCG)
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 445