ade7854 Analog Devices, Inc., ade7854 Datasheet - Page 50

• Manufacturer Part Number: ade7854
• Description: Poly Phase Multifunction Energy Metering Ic With Neutral Current Measurement
• Manufacturer: Analog Devices, Inc.

ADE7854
SPI Write Operation
The write operation using the SPI interface of the ADE7854
initiates when the master sets SS pin low and begins sending
one byte representing the address of the ADE7854 on the MOSI
line. The master sets data on the MOSI line starting with the
first high to low transition of SCLK. The SPI of the ADE7854
samples data on the low to high transitions of SCLK. The most
significant 7 bits of the address byte can have any value, but as a
good programming practice, they should be different from
b#0111000, the 7 bits used in the I
(READ/ WRITE ) of the address byte must be 0 for a write
operation. Next, the master sends the 16-bit address of the
register that is written and the 32, 16 or 8-bit value of that
register without losing any SCLK cycle. After the last bit is
transmitted, the master sets SS and SCLK lines high at the end
of SCLK cycle and the communication ends. The data lines
MOSI and MISO go in high impedance state.
SCLK
SCLK
MOSI
MISO
MOSI
SS
SS
0
0
0 0
0 0
2
C protocol. Bit 0
0
0
0 0 0
0 0 0
Figure 64. SPI Write operation of a 32-bit register
Figure 63. SPI read operation of a 32-bit register
1
0
15 14
15 14
Rev. PrC| Page 50 of 71
Reg Address
Reg Address
See Figure 64 for details of the SPI write operation.
HSDC Interface
The High Speed Data Capture (HSDC) interface is disabled
after default. It can be used only if the ADE7854 are configured
with I
conjunction with HSDC. Bit 6 (HSDCEN) in CONFIG[15:0]
register activates HSDC when set to 1. If bit HSDCEN is cleared
to 0, the default value, the HSDC interface is disabled. Setting
bit HSDCEN to 1 when SPI is in usage does not have any effect.
HSDC is an interface that is used to send to an external device,
usually a microprocessor or a DSP, up to thirteen 32-bit words.
The words represent the instantaneous values of the phase
currents and voltages, active and apparent powers. The registers
being transmitted are: IAWV[23:0], IBWV[23:0], ICWV[23:0],
VAWV[23:0], VBWV[23:0], VCWV[23:0], AWATT[23:0],
BWATT[23:0], CWATT[23:0], AVA[23:0], BVA[23:0] and
CVA[23:0]. All are 24-bit registers that are sign extended to 32-
2
C interface. The SPI interface cannot be used in
1
1
0
0
31 30
31 30
Preliminary Technical Data
Register Value
Register Value
1
1
0
0