mc9s12c32mpb16 Freescale Semiconductor, Inc, mc9s12c32mpb16 Datasheet - Page 278

• Manufacturer Part Number: mc9s12c32mpb16
• Description: Hcs12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 9 Clocks and Reset Generator (CRGV4) Block Description
9.4.10
All clocks are stopped in STOP mode, dependent of the setting of the PCE, PRE and PSTP bit. The
oscillator is disabled in STOP mode unless the PSTP bit is set. All counters and dividers remain frozen but
do not initialize. If the PRE or PCE bits are set, the RTI or COP continues to run in pseudo-stop mode. In
addition to disabling system and core clocks the CRG requests other functional units of the MCU (e.g.
voltage-regulator) to enter their individual power-saving modes (if available). This is the main difference
between pseudo-stop mode and wait mode.
After executing the STOP instruction the core requests the CRG to switch the MCU into stop mode. If the
PLLSEL bit remains set when entering stop mode, the CRG will switch the system and core clocks to
OSCCLK by clearing the PLLSEL bit. Then the CRG disables the PLL, disables the core clock and finally
disables the remaining system clocks. As soon as all clocks are switched off, stop mode is active.
If pseudo-stop mode (PSTP = 1) is entered from self-clock mode the CRG will continue to check the clock
quality until clock check is successful. The PLL and the voltage regulator (VREG) will remain enabled. If
full stop mode (PSTP = 0) is entered from self-clock mode an ongoing clock quality check will be stopped.
A complete timeout window check will be started when stop mode is exited again.
Wake-up from stop mode also depends on the setting of the PSTP bit.
278
CME
1
SCME
1
Low-Power Operation in Stop Mode
SCMIE
1
Table 9-11. Outcome of Clock Loss in Wait Mode (continued)
Clock failure -->
– VREG enabled,
– PLL enabled,
– SCM activated,
– Start Clock Quality Check,
– SCMIF set.
SCMIF generates Self-Clock Mode wakeup interrupt.
– Exit Wait Mode in SCM using PLL clock (f
– Continue to perform a additional Clock Quality Checks until OSCCLK
is o.k. again.
MC9S12C-Family / MC9S12GC-Family
Rev 01.23
CRG Actions
SCM
) as system clock,
Freescale Semiconductor