71M6541DSLASHFSLASHG datasheet(104/166 Pages) MAXIM

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71M6541D/F/G and 71M6542F/G Data Sheet

104

Rev 5

4.14

Flash Programming

4.14.1 Flash Programming via the ICE Port

Operational or test code can be programmed into the flash memory using either an in-circuit emulator or

the Flash Programmer Module (TFP-2) available from Maxim. The flash programming procedure uses the

E_RST, E_RXTX, and E_TCLK pins.

4.14.2 Flash Programming via the SPI Port

It is possible to erase, read and program the flash memory of the SPI port. See 2.5.10 SPI Slave Port for

a detailed description.

4.15

MPU Firmware Library

All application-specific MPU functions mentioned in 4 Application Information are featured in the

demonstration C source code supplied by Maxim. The code is available as part of the Demonstration Kit

for the 71M6541D/F/G and 71M6542F/G. The Demonstration Kits come with the preprogrammed with

demo firmware and mounted on a functional sample meter Demo Board. The Demo Boards allow for quick

and efficient evaluation of the IC without having to write firmware or having to supply an in-circuit

emulator (ICE).

4.16

Crystal Oscillator

The oscillator of the 71M6541D/F/G and 71M6542F/G drives a standard 32.768 kHz watch crystal. The

oscillator has been designed specifically to handle these crystals and is compatible with their high

impedance and limited power handling capability. The oscillator power dissipation is very low to

maximize the lifetime of any battery backup device attached to the VBAT_RTC pin.

Board layouts with minimum capacitance from XIN to XOUT require less battery current. Good layouts

have XIN and XOUT shielded from each other and from LCD and digital signals.

Since the oscillator is self-biasing, an external resistor must not be connected across the crystal.

4.17

Meter Calibration

Once the 71M654x energy meter device has been installed in a meter system, it must be calibrated. A

complete calibration includes the following:

•

Establishment of the reference temperature (e.g., typically 22 ⁰C)

•

Calibration of the metrology section, i.e., calibration for tolerances of the current sensors, voltage

dividers and signal conditioning components as well as of the internal reference voltage (VREF) at

the reference temperature (e.g., typically 22 ⁰C).

•

Calibration of the oscillator frequency using the RTCA_ADJ[7:0] I/O RAM register (I/O RAM 0x2504).

The metrology section can be calibrated using the gain and phase adjustment factors accessible to the

CE. The gain adjustment is used to compensate for tolerances of components used for signal conditioning,

especially the resistive components. Phase adjustment is provided to compensate for phase shifts

introduced by the current sensors or by the effects of reactive power supplies.

Due to the flexibility of the MPU firmware, any calibration method, such as calibration based on energy, or

current and voltage can be implemented. It is also possible to implement segment-wise calibration

(depending on current range).

The 71M6541D/F/G and 71M6542F/G support common industry standard calibration techniques, such

as single-point (energy-only), multi-point (energy, Vrms, Irms), and auto-calibration.

Maxim provides a calibration spreadsheet file to facilitate the calibration process. Contact your Maxim

representative to obtain a copy of the latest calibration spreadsheet file for the 71M654x.

71M6541D/F/G Datasheet(PDF) 104 Page - Maxim Integrated Products

71M6541D/F/G Datasheet(HTML) 104 Page - Maxim Integrated Products

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