71M6521DE TERIDIAN [Teridian Semiconductor Corporation], 71M6521DE Datasheet - Page 51

• Manufacturer Part Number: 71M6521DE
• Description: Energy Meter IC
• Manufacturer: TERIDIAN [Teridian Semiconductor Corporation]

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.
v1.0
V3P3SYS
rises
LCD
LCD_ONLY
PB
VBAT_OK
IE_PB -> 1
© 2005-2008 TERIDIAN Semiconductor Corporation
Figure 18: Operation Modes State Diagram
timer
IE_PLLRISE
-> 1
BROWNOUT
V3P3SYS
VBAT_OK
MISSION
RESET &
rises
IE_WAKE ->
1
PB
IE_PLLFALL
-> 1
V3P3SYS
71M6521DE/71M6521FE
falls
timer
SLEEP
VBAT_OK
SLEEP or
RESET &
VBAT_OK
RESET
V3P3SYS
rises
Energy Meter IC
V1 <= VBIAS
V1 > VBIAS
VBAT_OK
DATASHEET
JANUARY 2008
Page: 51 of 101