71M6521DE Datasheet, PDF (52/107 Pages) Teridian Semiconductor Corporation – Energy Meter IC

71M6521DE/DH/FE Data Sheet
MISSION
RESET
V3P3SYS
rises
V3P3SYS
falls
IE_PLLRISE
-> 1
IE_PLLFALL
-> 1
V3P3SYS
rises
V1 > VBIAS
V1 <= VBIAS
LCD_ONLY
BROWNOUT
IE_PB -> 1
PB
timer
IE_WAKE ->
1
V3P3SYS
rises
RESET &
VBAT_OK
SLEEP or
VBAT_OK
LCD
VBAT_OK
timer
PB
RESET &
VBAT_OK
VBAT_OK
SLEEP
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.
Page: 52 of 107
Rev 2