ADE7754AR Analog Devices Inc, ADE7754AR Datasheet - Page 29

• Manufacturer Part Number: ADE7754AR
• Description: IC ENERY METER 3PHASE 24-SOIC
• Manufacturer: Analog Devices Inc

Specifications of ADE7754AR

• Input Impedance: 370 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.8V
• Current - Supply: 7mA
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-SOIC (0.300", 7.50mm Width)
• Meter Type: 3 Phase
• For Use With: EVAL-ADE7754EBZ - BOARD EVALAUTION FOR ADE7754
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: AD71049AR; AD71049AR

Serial Read Operation
During a data read operation from the ADE7754, data is shifted
out at the DOUT logic output on the rising edge of SCLK. As
was the case with the data write operation, a data read must be
preceded by a write to the communications register.
With the ADE7754 in communications mode and CS logic low,
an 8-bit write to the communications register first takes place.
The MSB of this byte transfer must be a 0, indicating that the
next data transfer operation is a read. The six LSBs of this byte
contain the address of the register to be read. The ADE7754
starts shifting out of the register data on the next rising edge of
SCLK. See Figure 46. At this point, the DOUT logic output
switches from high impedance state and starts driving the data
bus. All remaining bits of register data are shifted out on subsequent
SCLK rising edges. The serial interface enters communications
REV. 0
SCLK
DOUT
SCLK
DIN
CS
DIN
CS
SCLK
t
t
1
DIN
1
1
0
0
0
X
t
2
A5
A5
X
t
COMMAND BYTE
3
COMMAND BYTE
MOST SIGNIFICANT BYTE
t
A4
A4
4
Figure 44. Serial Interface Write Timing Diagram
X
Figure 46. Serial Interface Read Timing Diagram
A3
A3
Figure 45. 12-Bit Serial Write Operation
X
A2
A2
DB11 DB10 DB9
t
5
A1
A1
A0
A0
t
–29–
7
DB8
t
9
t
11
mode again as soon as the read has been completed. The DOUT
logic output enters a high impedance state on the falling edge of
the last SCLK pulse. The read operation may be aborted by
bringing the CS logic input high before the data transfer is com-
pleted. The DOUT output enters a high impedance state on the
rising edge of CS.
When an ADE7754 register is addressed for a read operation,
the entire contents of that register are transferred to the serial
port. This allows the ADE7754 to modify its on-chip registers
without the risk of corrupting data during a multibyte transfer.
Note that when a read operation follows a write operation, the
read command (i.e., write to communications register) should
not happen for at least 1 µs after the end of the write operation.
If the read command is sent within 1 µs of the write operation,
the last byte of the write operation may be lost.
DB7
DB7
MOST SIGNIFICANT BYTE
DB7
MOST SIGNIFICANT BYTE
DB6
LEAST SIGNIFICANT BYTE
DB5
DB4
DB0
t
12
DB3
DB0
t
7
DB2
t
10
DB7
LEAST SIGNIFICANT BYTE
LEAST SIGNIFICANT BYTE
DB1
DB7
t
6
DB0
t
ADE7754
13
DB0
DB0
t
8