ade7566 Analog Devices, Inc., ade7566 Datasheet - Page 67

• Manufacturer Part Number: ade7566
• Description: Single-phase Energy Measurement Ic With 8052 Mcu, Rtc, And Lcd Driver
• Manufacturer: Analog Devices, Inc.

TEMPERATURE MEASUREMENT
To provide a digital temperature measurement, each
ADE7566/ADE7569 includes a dedicated ADC. An 8-bit
Temperature ADC Value SFR (TEMPADC, 0xD7), holds the
results of the temperature conversion. The resolution of the
temperature measurement is 0.78°C/LSB. There are two ways
to initiate a temperature conversion: a single temperature
measurement or background temperature measurements.
Single Temperature Measurement
Set the TEMP_ADC_GO bit in the Start ADC Measurement
SFR (ADCGO, 0xD8) to obtain a temperature measurement
(see Table 49). An interrupt is generated when the conversion is
complete and when the temperature measurement is available
in the Temperature ADC Value SFR (TEMPADC, 0xD7).
Background Temperature Measurements
Background temperature measurements are disabled by default.
To configure the background temperature measurement mode,
set a temperature measurement interval in the Peripheral ADC
Strobe Period SFR (STRBPER, 0xF9). Temperature measurements
are then performed periodically in the background (see Table 47).
When a temperature conversion completes, the new temperature
ADC value is compared to the last temperature ADC value that
created an interrupt. If the absolute difference between the two
values is greater than the setting in the TEMP_DIFF[2:0] bits in
the Temperature and Supply Delta SFR (DIFFPROG, 0xF3), a
TEMPADC interrupt is generated (see Table 48). This allows
temperature measurements to take place completely in the
background, only requiring MCU activity if the temperature
has changed more than a configurable delta.
To set up background temperature measurements, follow
these steps:
1.
2.
3.
Temperature ADC in PSM0, PSM1, and PSM2
Depending on the operating mode of the ADE7566/ADE7569,
a temperature conversion is initiated only by certain actions.
•
•
Initiate a single temperature measurement by setting the
TEMP_ADC_GO bit in the Start ADC Measurement SFR
(ADCGO, 0xD8).
Upon completion of this measurement, configure the
TEMP_DIFF[2:0] bits to establish the change in temperature
that triggers an interrupt.
Set up the interval for background temperature measurements
by configuring the TEMP_PERIOD[1:0] bits in the
Peripheral ADC Strobe Period SFR (STRBPER, 0xF9).
In PSM0 operating mode, the 8052 is active. Temperature
measurements are available in the background measurement
mode and by initiating a single measurement.
In PSM1 operating mode, the 8052 is active and the part
is battery powered. Single temperature measurements
can be initiated by setting the TEMP_ADC_GO bit in the
Start ADC Measurement SFR (ADCGO, 0xD8).
Background temperature measurements are not available.
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•
The Temperature ADC Value SFR (TEMPADC, 0xD7) is updated
with a new value only when a temperature ADC interrupt occurs.
Temperature ADC Interrupt
The temperature ADC can generate an ADC interrupt when at
least one of the following conditions occurs:
•
•
When the ADC interrupt occurs, a new value is available in the
Temperature ADC Value SFR (TEMPADC, 0xD7). Note that
there is no flag associated with this interrupt.
BATTERY MEASUREMENT
To provide a digital battery measurement, each ADE7566/
ADE7569 includes a dedicated ADC. The battery measurement is
available in an 8-bit SFR, the Battery ADC Value SFR
(BATADC, 0xDF). The battery measurement has a resolution of
14.6 mV/LSB. A battery conversion can be initiated by two
methods: a single battery measurement or background battery
measurements.
Single Battery Measurement
Set the BATT_ADC_GO bit in the Start ADC Measurement
SFR (ADCGO, 0xD8) to obtain a battery measurement. An
interrupt is generated when the conversion is done and when
the battery measurement is available in the Battery ADC Value
SFR (BATADC, 0xDF).
Background Battery Measurements
To configure background measurements for the battery,
establish a measurement interval in the Peripheral ADC Strobe
Period SFR (STRBPER, 0xF9). Battery measurements are then
performed periodically in the background (see Table 47).
When a battery conversion completes, the battery ADC value is
compared to the low battery threshold, established in the Battery
Detection Threshold SFR (BATVTH, 0xFA). If the battery ADC
value is below this threshold, a low battery flag is set. This low
battery flag is the FBAT bit in the Power Management Interrupt
Flag SFR (IPSMF, 0xF8), which is used for power supply moni-
toring. This low battery flag can be enabled to generate the PSM
interrupt by setting the EBAT bit in the Power Management
Interrupt Enable SFR (IPSME, 0xEC). This method allows
battery measurements to take place completely in the background,
only requiring MCU activity if the battery drops below a user-
specified threshold.
In PSM2 operating mode, the 8052 is not active.
Temperature conversions are available through the
background measurement mode only.
The difference between the new temperature ADC value and
the last temperature ADC value generating an ADC interrupt
is larger than the value set in the TEMP_DIFF[2:0] bits.
The temperature ADC conversion, initiated by setting Start
ADC Measurement SFR (ADCGO, 0xD8) finishes.
ADE7566/ADE7569