Datasheet
         71M6521DE/DH/FE Data Sheet 
Page: 2 of 107    Rev 3   
Table of Contents 
GENERAL DESCRIPTION ........................................................................................................................ 1
FEATURES ................................................................................................................................................ 1 
HARDWARE DESCRIPTION ..................................................................................................................... 10 
Hardware Overview ..................................................................................................................... 10 
Analog Front End (AFE) ............................................................................................................... 10 
Input Multiplexer ............................................................................................................ 10 
A/D Converter (ADC) ..................................................................................................... 11 
FIR Filter ........................................................................................................................ 11 
Voltage References ....................................................................................................... 11 
Temperature Sensor ...................................................................................................... 12 
Battery Monitor .............................................................................................................. 13 
Functional Description ................................................................................................... 13 
Digital Computation Engine (CE) ................................................................................................. 13 
Meter Equations ............................................................................................................ 14 
Description ................................................................................................................................... 14 
Real-Time Monitor ......................................................................................................... 15 
Pulse Generator ............................................................................................................ 15 
CE Functional Overview ................................................................................................ 15 
80515 MPU Core ........................................................................................................... 17 
Memory Organization .................................................................................................... 17 
Special Function Registers (SFRs) ................................................................................ 19 
Special Function Registers (Generic 80515 SFRs) ....................................................... 20 
Special Function Registers Specific to the 71M6521DE/DH/FE .................................... 22 
Instruction Set ................................................................................................................ 23 
UART ............................................................................................................................. 23 
Timers and Counters ..................................................................................................... 25 
WD Timer (Software Watchdog Timer) .......................................................................... 28 
Interrupts ....................................................................................................................... 30 
On-Chip Resources ..................................................................................................................... 38 
Oscillator ....................................................................................................................... 38 
PLL and Internal Clocks ................................................................................................ 38 
Real-Time Clock (RTC) ................................................................................................. 38 
Temperature Sensor ...................................................................................................... 38 
Physical Memory ........................................................................................................... 39 
Optical Interface ............................................................................................................ 40 
Digital I/O ....................................................................................................................... 40 
LCD Drivers ................................................................................................................... 42 
Battery Monitor .............................................................................................................. 42 
EEPROM Interface ........................................................................................................ 43 










