UM0402 datasheet(13/35 Pages) STMICROELECTRONICS

13 / 35 page

UM0402

Firmware features

13/35

In EEPROM, in the case of three months type MD the storing of month-wise maximum

demand and three month-wise maximum demand is defined as below:

4.3

Date and time configuration

RTC date and time can be set by the firmware itself. There is a RTC_init() function which

initializes the RTC with the specified date and time. The date and time to be initialized in

RTC should be specified in RTC_table[10] array. The definition of array is as below:

RTC_table[0] = write command and 7 bit address(0x00) = 0x80

RTC_table[1] = Seconds up to 0.01 in BCD format = value given by user

RTC_table[2] = ST and Seconds in BCD format = value given by user

RTC_table[3] = Minutes in BCD format = value given by user

RTC_table[4] = CEB, CB and Hours in BCD format = value given by user

RTC_table[5] = Day of week = value given by user

RTC_table[6] = Date of month in BCD format = value given by user

RTC_table[7] = Month in BCD format = value given by user

RTC_table[8] = Year = value given by user

RTC_table[9] = calibration value = value given by user

For more information, please refer to M41T94 datasheet of RTC used in the board.

Date and time can also be set by using the IRDA protocol. Please refer to the IEC 62056

PROTOCOL MODE C user manual.

4.4

Memory structure

The meter sensitive data are stored in EEPROM. M95256 256 Kbit EEPROM is used.

Below are details on memory organization.

4.4.1

Common storage for all maximum demand types

There is some common data stored at the start of EEPROM.

This data is saved in 89 Bytes of EEPROM_Union structure of EEPROM_DATA_Union data

type, and represents the energy count, the average maximum demand, application flags,

tariff definitions, energy counts and power down information.

Two pages of 64 Bytes are used for storing these 89 Bytes, as shown below:

Name

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

DEC

Index

678

Name

JAN, FEB, MAR

APR, MAY, JUN

JUL, AUG, SEP

OCT, NOV, DEC

Index

123

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