EVAL-ADE7763EB View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'EVAL-ADE7763EB' PDF : 56 Pages View PDF
ADE7763
times the maximum absolute value observed on the Channel 2
input. The contents of IPEAK represent the maximum absolute
value observed on the Channel 1 input. Reading the RSTVPEAK
and RSTIPEAK registers clears their respective contents after
the read operation.
INTERRUPTS
Interrupts are managed through the interrupt status register
(STATUS[15:0]) and the interrupt enable register
(IRQEN[15:0]). When an interrupt event occurs, the
corresponding flag in the status register is set to Logic 1—see
the Interrupt Status Register section. If the enable bit for this
interrupt in the interrupt enable register is Logic 1, the IRQ
logic output will go active low. The flag bits in the status register
are set irrespective of the state of the enable bits.
To determine the source of the interrupt, the system master
(MCU) should perform a read from the status register with
reset (RSTSTATUS[15:0]). This is achieved by carrying out a
read from Address 0Ch. The IRQ output goes logic high after
the completion of the interrupt status register read command—
see the Interrupt Timing section. When carrying out a read
with reset, the ADE7763 is designed to ensure that no interrupt
events are missed. If an interrupt event occurs as the status
register is being read, the event will not be lost and the IRQ
logic output will be guaranteed to go high for the duration of
the interrupt status register data transfer before going logic low
again to indicate the pending interrupt. See the next section for
a more detailed description.
t1
t2
IRQ
Using Interrupts with an MCU
Figure 38 shows a timing diagram with a suggested imple-
mentation of ADE7763 interrupt management using an MCU.
At time t1, the IRQ line goes active low, indicating that one or
more interrupt events have occurred. Tie the IRQ logic output to
a negative edge-triggered external interrupt on the MCU.
Configure the MCU to start executing its interrupt service
routine (ISR) when a negative edge is detected on the IRQ line.
After entering the ISR, disable all interrupts by using the global
interrupt enable bit. At this point, the MCU IRQ external
interrupt flag can be cleared to capture interrupt events that
occur during the current ISR. When the MCU interrupt flag is
cleared, a read from the status register with reset is carried out.
This causes the IRQ line to reset to logic high (t2)—see the
Interrupt Timing section. The status register contents are used
to determine the source of the interrupt(s) and, therefore, the
appropriate action to be taken. If a subsequent interrupt event
occurs during the ISR, that event will be recorded by the MCU
external interrupt flag being set again (t3). Upon the completion
of the ISR, the global interrupt mask is cleared (same
instruction cycle) and the external interrupt flag causes the
MCU to jump to its ISR again. This ensures that the MCU does
not miss any external interrupts.
MCU
INTERRUPT
t3
FLAG SET
MCU
PROGRAM
SEQUENCE
JUMP
TO
ISR
GLOBAL
INTERRUPT
MASK SET
CLEAR MCU
INTERRUPT
FLAG
READ
STATUS WITH
RESET (0x05)
ISR ACTION
(BASED ON STATUS CONTENTS)
ISR RETURN
GLOBAL INTERRUPT
MASK RESET
Figure 37. Interrupt Management
JUMP
TO
ISR
CS
SCLK
DIN
DOUT
IRQ
t1
t9
0
0
0
0
0
1
01
READ STATUS REGISTER COMMAND
t11
DB7
t11
DB0 DB7
DB0
STATUS REGISTER CONTENTS
Figure 38. Interrupt Timing
Rev. A | Page 18 of 56
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