Datasheet

71M6521DE/DH/FE Data Sheet
Page: 52 of 107 Rev 3
Figure 18: Operation Modes State Diagram
LCD Mode
In LCD mode, the data contained in the LCD_SEG registers is displayed, i.e. up to four LCD segments connected to
each of the pins SEG18 and SEG19 can be made to blink without the involvement of the MPU, which is disabled in
LCD mode.
This mode can be exited only by system power up, a timeout of the wake-up timer, or a push button. Figure 20 shows
the functional blocks active in LCD mode.
SLEEP Mode
In SLEEP mode, the battery current is minimized and only the Oscillator and RTC functions are active. This mode
can be exited only by system power-up, a timeout of the wake-up timer, or a push button event. Figure 21 shows the
functional blocks active in SLEEP mode.
V3P3SYS
rises
V3P3SYS
falls
MISSION
BROWNOUT
LCD
SLEEP or
V1 > VBIAS
V1 <= VBIAS
LCD_ONLY
RESET &
VBAT_OK
RESET
IE_PLLRISE
-> 1
IE_PLLFALL
-> 1
IE_PB -> 1
IE_WAKE ->
1
PB
timer
timer
PB
RESET &
V3P3SYS
rises
V3P3SYS
rises
VBAT_OK
VBAT_OK
VBAT_OK
VBAT_OK
SLEEP