AD7147A Analog Devices, AD7147A Datasheet - Page 38

• Manufacturer Part Number: AD7147A
• Manufacturer: Analog Devices

Specifications of AD7147A

• Resolution (bits): 16bit
• # Chan: 13
• Sample Rate: 111SPS
• Interface: I²C/Ser 2-Wire,Ser,SPI
• Analog Input Type: Capacitive
• Ain Range: ± 8 pF (Delta C)
• Adc Architecture: Sigma-Delta
• Pkg Type: CSP

AD7147A
POWER-UP SEQUENCE
To power up the AD7147A, use the following sequence when
initially developing the AD7147A and microprocessor serial
interface:
1.
2.
3.
CONVERSION
AD7147A INT
INTERFACE
POWER
SERIAL
STAGE
Turn on the power supplies to the AD7147A.
Write to the Bank 2 registers at Address 0x080 through
Address 0x0DF. These registers are contiguous; therefore, a
sequential register write sequence can be applied.
Note that the Bank 2 register values are unique for each
application. Register values come from characterization of
the sensor in the application. The characterization process
is outlined in the AN-929 Application Note, available from
Analog Devices.
Write to the Bank 1 registers at Address 0x000 through
Address 0x007, outlined as follows. These registers are
contiguous; therefore, a sequential register write sequence
can be applied (see Figure 49 and Figure 54).
Caution: At this time, Address 0x001 must remain set
to a default value of 0x0000 during this contiguous write
operation.
Register values:
Address 0x000 = 0x82B2
Address 0x001 = 0x000
Address 0x002 = 0x3230 (depends on number of
conversion stages used)
Address 0x003 = 0x419
HOST
CONVERSION STAGES DISABLED
0
1
2
Figure 58. Recommended Start-Up Sequence
3
FIRST CONVERSION SEQUENCE
4
5
Rev. B | Page 38 of 68
6
7
8
9
10 11
4.
5.
6.
Address 0x004 = 832
Address 0x005 = interrupt enable register (depends on
required interrupt behavior)
Address 0x006 = interrupt enable register (depends on
required interrupt behavior)
Address 0x007 = interrupt enable register (depends on
required interrupt behavior)
Write to the Bank 1 register, Address 0x001 = 0x0FFF
(depends on number of conversion stages used).
Read back the corresponding interrupt status register at
Address 0x008, Address 0x009, or Address 0x00A. This is
determined by the interrupt output configuration, as
explained in the Interrupt Output section.
Note that the specific registers required to be read back
depend on each application. For buttons, the interrupt
status registers are read back while other sensors read data
back from the AD7147A according to the slider or wheel
algorithm requirements. Analog Devices can provide this
information after the user develops the sensor board.
Repeat Step 5 every time INT is asserted.
0
1
2
SECOND CONVERSION
SEQUENCE
9
10 11
0
1
2
THIRD CONVERSION
SEQUENCE
9
10
11
0
1