ADE7758
ACCESSING THE ADE7758 ON-CHIP REGISTERS
All ADE7758 functionality is accessed via the on-chip registers.
Each register is accessed by first writing to the communications
register and then transferring the register data. For a full
description of the serial interface protocol, see the ADE7758
Serial Interface section.
Rev. A | Page 58 of 68
COMMUNICATIONS REGISTER
The communications register is an 8-bit, write-only register that
controls the serial data transfer between the ADE7758 and the
host processor. All data transfer operations must begin with a
write to the communications register. The data written to the
communications register determines whether the next operation
is a read or a write and which register is being accessed. Table 12
outlines the bit designations for the communications register.
Table 12. Communications Register
Bit Location
Bit Mnemonic
0 to 6
A0 to A6
Description
The seven LSBs of the communications register specify the register for the data transfer operation.
Table 13 lists the address of each ADE7758 on-chip register.
When this bit is a Logic 1, the data transfer operation immediately following the write to the
communications register is interpreted as a write to the ADE7758. When this bit is a Logic 0, the data
transfer operation immediately following the write to the communications register is interpreted as a
read operation.
7
W/R
DB7
W/R A6
DB6
DB5
A5
DB4
A4
DB3
A3
DB2
A2
DB1
A1
DB0
A0
Table 13. ADE7758 Register List
Address
[A6:A0]
Name
0x00
Reserved
0x01
AWATTHR
R/W
1
–
R
Length
16
Default
Value
0
Description
Reserved.
Watt-Hour Accumulation Register for Phase A. Active power is accumulated over
time in this read-only register. The AWATTHR register can hold a maximum of
0.52 seconds of active energy information with full-scale analog inputs before it
overflows (see the Active Energy Calculation section). Bit 0 and Bit 1 of the
COMPMODE register determine how the active energy is processed from the six
analog inputs.
Watt-Hour Accumulation Register for Phase B.
Watt-Hour Accumulation Register for Phase C.
VAR-Hour Accumulation Register for Phase A. Reactive power is accumulated
over time in this read-only register. The AVARHR register can hold a maximum of
0.52 seconds of reactive energy information with full-scale analog inputs before
it overflows (see the Reactive Energy Calculation section). Bit 0 and Bit 1 of the
COMPMODE register determine how the reactive energy is processed from the
six analog inputs.
VAR-Hour Accumulation Register for Phase B.
VAR-Hour Accumulation Register for Phase C.
VA-Hour Accumulation Register for Phase A. Apparent power is accumulated
over time in this read-only register. The AVAHR register can hold a maximum of
1.15 seconds of apparent energy information with full-scale analog inputs before
it overflows (see the Apparent Energy Calculation section). Bit 0 and Bit 1 of the
COMPMODE register determine how the apparent energy is processed from the
six analog inputs.
VA-Hour Accumulation Register for Phase B.
VA-Hour Accumulation Register for Phase C.
Phase A Current Channel RMS Register. The register contains the rms component
of the Phase A input of the current channel. The source is selected by data bits in
the mode register.
Phase B Current Channel RMS Register.
Phase C Current Channel RMS Register.
Phase A Voltage Channel RMS Register.
Phase B Voltage Channel RMS Register.
0x02
0x03
0x04
BWATTHR
CWATTHR
AVARHR
R
R
R
16
16
16
0
0
0
0x05
0x06
0x07
BVARHR
CVARHR
AVAHR
R
R
R
16
16
16
0
0
0
0x08
0x09
0x0A
BVAHR
CVAHR
AIRMS
R
R
R
16
16
24
0
0
0
0x0B
0x0C
0x0D
0x0E
BIRMS
CIRMS
AVRMS
BVRMS
R
R
R
R
24
24
24
24
0
0
0
0