71M6521BE
Energy Meter IC
DATA SHEET
JANUARY 2008
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. The
V3P3D output pin is inactive 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 is active. The V3P3D output pin is inactive in LCD
mode. 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.
System Power
MISSION
Battery Power (nonvolatile Supply)
Circuit Function
BROWNOUT
LCD
SLEEP
CE
Yes
Yes
Yes
--
Yes
--
--
--
--
--
--
--
CE Data RAM
FIR
Analog circuits:
PLL, ADC, VREF, BME, etc.
Yes
--
--
--
--
--
4.92MHz
(from PLL)
Yes
28.672kHz
(7/8 of 32768Hz)
Yes
MPU clock rate
MPU_DIV
--
--
--
--
--
--
--
--
--
--
ICE
Yes
Yes
DIO Pins
Yes
Yes
--
Watchdog Timer
LCD
Yes
Yes
--
Yes
Yes
Yes
--
EEPROM Interface (2-wire)
EEPROM Interface (3-wire)
UART
Yes
Yes (8kb/s)
Yes (16kb/s)
Yes
Yes
--
Yes
--
Optical TX modulation
Flash Read
Flash Page Erase
Flash Write
Yes
Yes
Yes
Yes
Yes
--
--
--
--
--
--
--
--
--
--
--
Yes
Yes
--
RAM Read and Write
Yes
Wakeup Timer
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
--
Yes
Yes
--
Crystal oscillator
DRAM data preservation
V3P3D voltage output
--
--
Table 59: Available Circuit Functions (“—“ means “not active)
V1.0
© 2005-2008 TERIDIAN Semiconductor Corporation
Page: 51 of 97
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
