Datasheet

ADE7880 Data Sheet
Rev. A | Page 24 of 104
HARDWARE RESET
The ADE7880 has a
RESET
pin. If the is in PSM0
mode and the
ADE7880
RESET
pin is set low, then the enters
the hardware reset state. The must be in PSM0 mode
for a hardware reset to be considered. Setting the
ADE7880
ADE7880
RESET
pin
low while the is in PSM1, PSM2, and PSM3 modes
does not have any effect.
ADE7880
If the ADE7880 is in PSM0 mode and the
RESET
pin is toggled
from high to low and then back to high after at least 10 µs, all the
registers are set to their default values, including the CONFIG2 and
LPOILVL registers. The signals the end of the transition
period by triggering the
ADE7880
IRQ1
interrupt pin low and setting Bit 15
(RSTDONE) in the STATUS1 register to 1. This bit is 0 during
the transition period and becomes 1 when the transition ends.
The status bit is cleared and the
IRQ1
pin is returned high by
writing to the STATUS1 register with the corresponding bit set
to 1.
After a hardware reset, the DSP is in idle mode, which means it
does not execute any instruction.
Because the I
2
C port is the default serial port of the ADE7880, it
becomes active after a reset state. If SPI is the port used by the
external microprocessor, the procedure to enable it must be
repeated immediately after the
RESET
pin is toggled back to
high (see the section for details). Serial Interfaces
At this point, it is recommended to initialize all of the ADE7880
registers and then write 0x0001 into the Run register to start the
DSP. See the Digital Signal Processor section for details on the
Run register.
SOFTWARE RESET FUNCTIONALITY
Bit 7 (SWRST) in the CONFIG register manages the software
reset functionality in PSM0 mode. The default value of this bit is 0.
If this bit is set to 1, then the ADE7880 enters the software reset
state. In this state, almost all internal registers are set to their
default values. In addition, the choice of which serial port, I
2
C or
SPI, is in use remains unchanged if the lock-in procedure has
been executed previously (see the Serial Interfaces section for
details). The registers that maintain their values despite the
SWRST bit being set to 1 are the CONFIG2 and LPOILVL
registers. When the software reset ends, Bit 7 (SWRST) in the
CONFIG register is cleared to 0, the
IRQ1
interrupt pin is set
low, and Bit 15 (RSTDONE) in the STATUS1 register is set to 1.
This bit is 0 during the transition period and becomes 1 when
the transition ends. The status bit is cleared and the
IRQ1
pin is
set back high by writing to the STATUS1 register with the
corresponding bit set to 1.
After a software reset ends, the DSP is in idle mode, which
means it does not execute any instruction. As a good programming
practice, it is recommended to initialize all the ADE7880 registers
and then write 0x0001 into the Run register to start the DSP
(see the Digital Signal Processor section for details on the Run
register).
Software reset functionality is not available in PSM1, PSM2, or
PSM3 mode.