ADE7569 Datasheet, PDF (33/136 Pages) Analog Devices – Single-Phase Energy Measurement IC with 8052 MCU, RTC, and LCD Driver

Preliminary Technical Data
ADE7566/ADE7569
TRANSITIONING BETWEEN OPERATING MODES
The operating mode of the ADE7566/ADE7569 is determined
by the power supply connected to VSW. Therefore, changes in
the power supply such as when VSW switches from VDD to VBAT,
or when VSW switches to VDD, alters the operating mode. This
section describes events that change the operating mode.
Automatic Battery Switchover (PSM0 to PSM1)
If any of the enabled battery switchover events occur (see the
Battery Switchover section), VSW switches to VBAT. This switchover
results in a transition from the PSM0 to PSM1 operating mode.
When battery switchover occurs, the analog circuitry used in
the ADE energy measurement DSP is disabled. To reduce power
consumption, the user code can initiate a transition to PSM2.
Entering Sleep Mode (PSM1 to PSM2)
To reduce power consumption when VSW is connected to VBAT,
user code can initiate sleep mode, PSM2, by setting Bit 4 in the
Power Control SFR (POWCON, 0xC5) to shut down the MCU
core. Events capable of waking the MCU can be enabled (see the
3.3 V Peripherals and Wake-Up Events section).
Servicing Wake-Up Events (PSM2 to PSM1)
The ADE7566/ADE7569 may need to wake up from PSM2 to
service wake-up events (see the 3.3 V Peripherals and Wake-Up
Events section). PSM1 code execution begins at the power-on
reset vector. After servicing the wake-up event, the ADE7566/
ADE7569 can return to PSM2 by setting Bit 4 in the Power
Control SFR (POWCON, 0xC5) to shut down the MCU core.
Automatic Switch to V_DD (PSM2 to PSM0)
If the conditions to switch VSW from VBAT to VDD occur (see the
Battery Switchover section), the operating mode switches to
PSM0. When this switch occurs, the MCU core and the analog
circuitry used in the ADE energy measurement DSP
automatically restarts. PSM0 code execution begins at the
power-on reset vector.
Automatic Switch to V_DD (PSM1 to PSM0)
If the conditions to switch VSW from VBAT to VDD occur (see the
Battery Switchover section), the operating mode switches to
PSM0. When this switch occurs, the analog circuitry used in the
ADE energy measurement DSP automatically restarts. Note that
code execution continues normally. A software reset can be
performed to start PSM0 code execution at the power-on reset
vector.
USING THE POWER MANAGEMENT FEATURES
Because program flow is different for each operating mode, the
status of VSW must be known at all times. The FVSW bit in the
Power Management Interrupt Flag SFR (IPSMF, 0xF8) indicates
what VSW is connected to. This bit can be used to control program
flow on wake-up. Because code execution always starts at the
power-on reset vector, Bit 6 of the Peripheral Configuration
SFR (PERIPH, 0xF4) can be tested to determine which power
supply is being used and to branch to normal code execution, or
to wake up event code execution. Power supply events can also
occur when the MCU core is active. To be aware of the events
that change what VSW is connected to, use the following guidelines:
• Enable the battery switchover interrupt (EVSW) if
VSW = VDD at power-up.
• Enable the power supply restored interrupt (EPSR) if
VSW = VBAT at power-up.
An early warning that battery switchover is about to occur is
provided by SAG detection and possibly low VDCIN detection
(see the Battery Switchover section).
For a user-controlled battery switchover, enable automatic
battery switchover on low VDD only. Then, enable the low VDCIN
event to generate the PSM interrupt. When a low VDCIN event
occurs, start data backup. Upon completion of the data backup,
enable battery switchover on low VDCIN. Battery switchover
occurs 30 ms later.
POWER SUPPLY
RESTORED
PSMO
NORMAL MODE
V_SW CONNECTED TO V_DD
AUTOMATIC BATTERY
SWITCHOVER
PSM1
BATTERY MODE
V_SW CONNECTED TO V_BAT
POWER SUPPLY
RESTORED
WAKEUP
EVENT
PSM2
SLEEP MODE
V_SW CONNECTED TO V_BAT
USER CODE DIRECTS MCU
TO SHUTDOWN CORE AFTER
SERVICING WAKE-UP EVENT
Figure 28. Transitioning Between Operating Modes
Rev. PrA | Page 33 of 136