AD7156 Analog Devices, AD7156 Datasheet - Page 20

• Manufacturer Part Number: AD7156
• Manufacturer: Analog Devices

Specifications of AD7156

• Resolution (bits): 12bit
• # Chan: 2
• Sample Rate: 100SPS
• Interface: I²C/Ser 2-Wire,Ser
• Analog Input Type: Capacitive
• Ain Range: 0.5 pF,1 pF,2 pF,4 pF
• Pkg Type: CSP

AD7156
CONFIGURATION REGISTER
Address Pointer 0x0F
8 Bits, Read/Write, Factory Preset 0x19
Table 12. Configuration Register Bit Map
1
Table 13.Configuration Register Bit Descriptions
Bit
7
6
5
4
3
2
1
0
The default values are given in parentheses.
ThrFixed
Bit 7
(0)
Mnemonic
ThrFixed
ThrMD1
ThrMD0
EnCh1
EnCh2
MD2
MD1
MD0
ThrMD1
Description
ThrFixed = 1 sets the fixed threshold mode; the outputs reflect the comparison of data and a fixed (constant)
value of the threshold registers.
ThrFixed = 0 sets the adaptive threshold mode; the outputs reflect the comparison of data to the adaptive
thresholds. The adaptive threshold is set dynamically, based on the history of the previous data.
These bits set the output comparators mode
ThrMD1
0
0
1
1
Enables conversion on Channel 1
Enables conversion on Channel 2
Converter mode of operation setup
MD2
0
0
0
0
1
Bit 6
(0)
MD1
0
0
1
1
X
ThrMD0
0
1
0
1
1
ThrMD0
MD0
0
1
0
1
X
Bit 5
(0)
Mode
Idle
Continuous
Conversion
Single conversion
Power-down
Reserved
Threshold Mode
Negative
Positive
In-window
Out-window
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EnCh1
Bit 4
(1)
Adaptive Threshold Mode
Data < average – sensitivity
Data > average + sensitivity
Data > average – sensitivity
and
Data < average + sensitivity
Data < average – sensitivity
or
Data > average + sensitivity
Description
The part is fully powered up, but performing no conversion.
The part is repeatedly performing conversions on the
enabled channel(s); if two channels are enabled, the part is
sequentially switching between them.
The part performs a single conversion on the enabled
channel; if two channels are enabled, the part performs two
conversions, one on each channel. After finishing the
conversion(s), the part goes to the idle mode.
The part powers down the on-chip circuits, except the
digital interface.
Do not use these modes.
EnCh2
Bit 3
(1)
Output Active When
Bit 2
MD2
(0)
Fixed Threshold Mode
Data < threshold
Data > threshold
Bit 1
MD1
(0)
Bit 0
MD0
(1)