Datasheet

Chapter 5 Resets, Interrupts, and General System Control
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 5
76 Freescale Semiconductor
5.8.10 System Power Management Status and Control 3 Register
(SPMSC3)
This high page register is used to report the status of the low voltage warning function and to select the
low voltage detect trip voltage.
76543210
RLVWF 0
LVDV LV W V
0000
W LVWAC K
POR:
0
1
1
LVWF will be set in the case when V
Supply
transitions below the trip point or after reset and V
Supply
is already below V
LVW
.
0000000
LVD:
0
1
0UU0000
Any other
reset:
0
1
0UU0000
= Unimplemented or Reserved U= Unaffected by reset
Figure 5-12. System Power Management Status and Control 3 Register (SPMSC3)
Table 5-14. SPMSC3 Register Field Descriptions
Field Description
7
LVWF
Low-Voltage Warning Flag — The LVWF bit indicates the low voltage warning status.
0 Low voltage warning not present.
1 Low voltage warning is present or was present.
6
LVWACK
Low-Voltage Warning Acknowledge — The LVWF bit indicates the low voltage warning status. Writing a 1 to
LVWACK clears LVWF to a 0 if a low voltage warning is not present.
5
LVDV
Low-Voltage Detect Voltage Select — The LVDV bit selects the LVD trip point voltage (V
LVD
).
0 Low trip point selected (V
LVD
= V
LVDL
).
1 High trip point selected (V
LVD
= V
LVD H
).
4
LVWV
Low-Voltage Warning Voltage Select — The LVWV bit selects the LVW trip point voltage (V
LVW
).
0 Low trip point selected (V
LVW
= V
LVW L
).
1 High trip point selected (V
LVW
= V
LVWH
).