71M6541D Datasheet, PDF (3/166 Pages) Maxim Integrated Products – 0.1% Accuracy Over 2000:1 Current Range Energy Meter ICs

71M6541D/F/G and 71M6542F/G Data Sheet
3.3 Fault and Reset Behavior...................................................................................................... 85
3.3.1 Events at Power-Down .............................................................................................. 85
3.3.2 IC Behavior at Low Battery Voltage ........................................................................... 86
3.3.3 Reset Sequence........................................................................................................ 86
3.3.4 Watchdog Timer Reset .............................................................................................. 86
3.4 Wake Up Behavior ................................................................................................................ 87
3.4.1 Wake on Hardware Events ........................................................................................ 87
3.4.2 Wake on Timer.......................................................................................................... 90
3.5 Data Flow and MPU/CE Communication ............................................................................... 91
4 Application Information............................................................................................................... 92
4.1 Connecting 5 V Devices........................................................................................................ 92
4.2 Direct Connection of Sensors ................................................................................................ 92
4.3 71M6541D/F/G Using Local Sensors..................................................................................... 93
4.4 71M6541D/F/G Using 71M6x01and Current Shunts .............................................................. 94
4.5 71M6542F/G Using Local Sensors ........................................................................................ 95
4.6 71M6542F/G Using 71M6x01 and Current Shunts................................................................. 96
4.7 Metrology Temperature Compensation.................................................................................. 97
4.7.1 Voltage Reference Precision ..................................................................................... 97
4.7.2 Temperature Coefficients for the 71M654x ................................................................ 97
4.7.3 Temperature Compensation for VREF with Local Sensors......................................... 98
4.7.4 Temperature Compensation for VREF with Remote Sensor....................................... 99
4.8 Connecting I²C EEPROMs .................................................................................................. 100
4.9 Connecting Three-Wire EEPROMs ..................................................................................... 101
4.10 UART0 (TX/RX) .................................................................................................................. 101
4.11 Optical Interface (UART1) ................................................................................................... 101
4.12 Connecting the Reset Pin.................................................................................................... 102
4.13 Connecting the Emulator Port Pins...................................................................................... 102
4.14 Flash Programming............................................................................................................. 104
4.14.1 Flash Programming via the ICE Port........................................................................ 104
4.14.2 Flash Programming via the SPI Port ........................................................................ 104
4.15 MPU Firmware Library ........................................................................................................ 104
4.16 Crystal Oscillator................................................................................................................. 104
4.17 Meter Calibration................................................................................................................. 104
5 Firmware Interface..................................................................................................................... 105
5.1 I/O RAM Map –Functional Order ......................................................................................... 105
5.2 I/O RAM Map – Alphabetical Order ..................................................................................... 111
5.3 CE Interface Description ..................................................................................................... 125
5.3.1 CE Program ............................................................................................................ 125
5.3.2 CE Data Format ...................................................................................................... 125
5.3.3 Constants................................................................................................................ 125
5.3.4 Environment............................................................................................................ 126
5.3.5 CE Calculations....................................................................................................... 126
5.3.6 CE Front End Data (Raw Data)................................................................................ 127
5.3.7 FCE Status and Control........................................................................................... 127
5.3.8 CE Transfer Variables ............................................................................................. 129
5.3.9 Pulse Generation..................................................................................................... 132
5.3.10 Other CE Parameters.............................................................................................. 134
5.3.11 CE Calibration Parameters ...................................................................................... 135
5.3.12 CE Flow Diagrams .................................................................................................. 136
6 Electrical Specifications............................................................................................................ 138