71M6521DEIM-DB Maxim Integrated Products, 71M6521DEIM-DB Datasheet - Page 69

• Manufacturer Part Number: 71M6521DEIM-DB
• Description: Power Management Modules & Development Tools 71M6521DE DEMO BOARD M6521DE DEMO BOARD
• Manufacturer: Maxim Integrated Products

Specifications of 71M6521DEIM-DB

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

71M652X Software User’s Guide
At the end of each accumulation interval, an MPU interrupt, the "xfer_interrupt" occurs (see ce.c, xfer_busy_isr())
occurs. This is the signal for the MPU to copy the above data to stable storage for further use.
At this time, the MPU performs creep detection (meter.c Apply_Creep() ). If the measured voltage, current and/or
power is below the minimum, no results for volts, current or watts are reported. If the voltage is below the threshold, no
frequency or edge counts are reported. If the current is below the minimum, no current, Wh, VARh or VAh are
reported.
The MPU's creep thresholds are configurable (VThrshld, IThrshld).
The MPU calculates human-readable values, and accumulates cumulative quantities (see meter.c, meter_run.ce.c,
ce_update() ). The MPU scales these values to the voltage and current sensors used on the PCB (see VMAX and
IMAX).
Wh and VARh quantities are signed, permitting the MPU to perform net metering by assigning negative values to
"export" and positive values to "import" (see meter.c. Wh.c, VAh.c and VARh.c.
Meters require more precision than standard C floating point provides. The Demo Code has reusable calculations for
meter math (mmath.c). These automatically convert CE counts into a major running count of Wh, and a minor
remainder of CE counts.
The MPU also places a scaled value into the CE RAM for each pulse output (meter.c, meter_run(), pulse_src.c,
selectpulses() ). This adjusts the pulse output frequency in such a way as to reflect that accumulation's contribution to
the total pulse interval. Pulse intervals are cumulative, and cumulatively accurate, even though the frequency is
updated only periodically.
Placing the pulse value selection logic into the MPU software means that any quantity from any phase or combination
of phases can control either pulse output (see PulseSrcFunc[] for a list of transfer functions).
The MPU also performs temperature adjustments of the real-time clock (rtc_10.c, RTC_Trim(), RTC_Adjust_Trim() ).
The Demo Code can adjust the clock speed to a resolution of 1 part per billion, roughly one second per thirty years.
The adjustments include offset (Y_CAL), temperature-linear (Y_CALC) and temperature-squared (Y_CALC2)
parameters.
Once a human-readable quantity is available, it can be translated into a set of segments (meter.c, lcd.c) to display on
the liquid crystal display, or read from a register in memory by means of the command-line interface (cli.c), or possibly
some other serial protocol such as Flag (see flag.c) or NEMA.
The interface between the CE and the MPU is described completely in the 71M6521 Data Sheet.
It is possible to implement code that functions as a boot loader. This feature is useful for field updates and various test
scenarios.
See the TERIDIAN Application Note number 031 for details.
The functionality of the Demo Code is implemented in the following files and directories:
Revision 1.7
5.7
5.8
5.9
1.
CE/MPU INTERFACE
BOOT LOADER
SOURCE FILES
CLI:
access.c
access_x.c
c_serial.c
cli.c
cmd_ce.c
cmd_misc.c
help.c
io.c
load.c
profile.c
ser0cli.c
ser1cli.c
sercli.c
Command Line Interface – General Commands
command line interface routines
upload and download
SFR, I/O RAM, MPU and CE memory access routines
extended memory access routines
parser for command line interface
sub-parser for CE commands
sub-parser for RTC, EEPROM, trim and PS commands
display of help text
number conversion functions and auxiliary routines for CLI
data collection for support of profile command
buffer serial I/O for the CLI
© Copyright 2005-2007 TERIDIAN Semiconductor Corporation
TERIDIAN Proprietary
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