NXP Semiconductors MC9S12G - Page 364

S12 Clock, Reset and Power Management Unit (S12CPMU)
MC9S12G Family Reference Manual Rev.1.27
366 NXP Semiconductors
Read: Anytime
Write: Refer to each bit for individual write conditions
0x0037
76543210
R
RTIF PORF LVRF LOCKIF
LOCK
ILAF OSCIF
UPOSC
W
Reset 0 Note 1 Note 2 0 0 Note 3 0 0
1. PORF is set to 1 when a power on reset occurs. Unaffected by System Reset.
2. LVRF is set to 1 when a low voltage reset occurs. Unaffected by System Reset. Set by power on reset.
3. ILAF is set to 1 when an illegal address reset occurs. Unaffected by System Reset. Cleared by power on reset.
= Unimplemented or Reserved
Figure 10-7. S12CPMU Flags Register (CPMUFLG)
Table 10-3. CPMUFLG Field Descriptions
Field Description
7
RTIF
Real Time Interrupt Flag — RTIF is set to 1 at the end of the RTI period. This flag can only be cleared by writing
a 1. Writing a 0 has no effect. If enabled (RTIE=1), RTIF causes an interrupt request.
0 RTI time-out has not yet occurred.
1 RTI time-out has occurred.
6
PORF
Power on Reset Flag — PORF is set to 1 when a power on reset occurs. This flag can only be cleared by writing
a 1. Writing a 0 has no effect.
0 Power on reset has not occurred.
1 Power on reset has occurred.
5
LVRF
Low Voltage Reset Flag — LVRF is set to 1 when a low voltage reset occurs. This flag can only be cleared by
writing a 1. Writing a 0 has no effect.
0 Low voltage reset has not occurred.
1 Low voltage reset has occurred.
4
LOCKIF
PLL Lock Interrupt Flag — LOCKIF is set to 1 when LOCK status bit changes. This flag can only be cleared by
writing a 1. Writing a 0 has no effect.If enabled (LOCKIE=1), LOCKIF causes an interrupt request.
0 No change in LOCK bit.
1 LOCK bit has changed.
3
LOCK
Lock Status Bit — LOCK reflects the current state of PLL lock condition. Writes have no effect. While PLL is
unlocked (LOCK=0) fPLL is fVCO / 4 to protect the system from high core clock frequencies during the PLL
stabilization time tlock.
0 VCOCLK is not within the desired tolerance of the target frequency.
f
PLL
= f
VCO
/4.
1 VCOCLK is within the desired tolerance of the target frequency.
f
PLL
= f
VCO
/(POSTDIV+1).
2
ILAF
Illegal Address Reset Flag — ILAF is set to 1 when an illegal address reset occurs. Refer to MMC chapter for
details. This flag can only be cleared by writing a 1. Writing a 0 has no effect.
0 Illegal address reset has not occurred.
1 Illegal address reset has occurred.