Maxim Integrated 71M6533-DB - Manual (Page 25)

71M6533- DB Demo Board User’s Manual
Page: 25 of 75 ` REV 3
1.9.5 AUTOMATIC GAINS CALIBRATION
The Demo Code is able to perform a single-point fast automatic calibration, as described in section 2.2. This
calibration is performed for channels A, B, and C only, not for the NEUTRAL channel. The steps required for the
calibration are:
1. Enter operating values for voltage and current in I/O RAM. The voltage is entered at MPU address
0x10 (e.g. with the command )10=+2400 for 240V), the current is entered at 0x11 (e.g. with the
command )11=+300 for 30A) and the duration measured in accumulation intervals is entered at 0x0F.
2. The operating voltage and current defined in step 1 must be applied at a zero degree phase angle to
the meter (Demo Board).
3. The CLB (Begin Calibration) command must be entered via the serial interface. The operating voltage
and current must be maintained accurately while the calibration is being performed.
4. The calibration procedure will automatically reset CE addresses used to store the calibration factors to
their default values prior to starting the calibration. Automatic calibration also reads the chip
temperature and enters it at the proper CE location temperature compensation.
5. CE addresses 0x10 to 0x15 and 0x18 to 0x1A will now show the new values determined by the auto-
calibration procedure. These values can be stored in EEPROM by issuing the CLS command.
Tip: Current transformers of a given type usually have very similar phase angle for identical operating
conditions. If the phase angle is accurately determined for one current transformer, the corresponding
phase adjustment coefficient PHADJ_X can be entered for all calibrated units.
1.9.6 LOADING THE CODE FOR THE 6533 INTO THE DEMO BOARD
Hardware Interface for Programming: The 71M6533 IC provides an interface for loading code into the
internal flash memory. This interface consists of the following signals:
E_RXTX (data), E_TCLK (clock), E_RST (reset), ICE_E (ICE enable)
These signals, along with V3P3D and GND are available on the emulator headers J14 and J17. Production
meters may be equipped with simple programming connectors, such as the 6x1 header used for J17.
Programming of the flash memory requires a specific in-circuit emulator, the ADM51 by Signum Systems
(http//www.signumsystems.com) or the Flash Programmer (TFP2) available through Maxim distributors.
Chips may also be programmed before they are soldered to the board.
In-Circuit Emulator: If firmware exists in the 71M6533 flash memory; it has to be erased before loading a new
file into memory. Figure 1-7 and Figure 1-8 show the emulator software active. In order to erase the flash
memory, the RESET button of the emulator software has to be clicked followed by the ERASE button ().
Once the flash memory is erased, the new file can be loaded using the commands File followed by Load. The
dialog box shown in Figure 1-8 will then appear making it possible to select the file to be loaded by clicking the
Browse button. Once the file is selected, pressing the OK button will load the file into the flash memory of the
71M6533 IC.
At this point, the emulator probe (cable) can be removed. Once the 71M6533 IC is reset using the reset button
on the Demo Board, the new code starts executing.
Flash Programmer Module (TFP2): Follow the instructions given in the User Manual for the TFP2.