D7
D6
D5
D4
D3
D2
D1
D0
1
9
1
9
Ack
by
Slave
Start by
Master
R/W
Ack
by
Slave
Frame 1
Serial Bus Address Byte
from Master
Frame 2
Slave Register Address (ADDR) from
Master
A2
A0
A1
A3
A4
A5
A6
SCL
SDA
SCL
(continued)
SDA
(continued)
D7
D6
D5
D4
D3
D2
D1
D0
1
9
Ack
by
Slave
Repeat
Start by
Master
Ack
by
Master
Stop
by
Master
1
9
Frame 3
Serial Bus Address Byte
from Master
R/W
A2
A0
A1
A3
A4
A5
A6
Frame 4
Data Byte from Slave Register ADDR
SCL
(continued)
SDA
(continued)
D7
D6
D5
D4
D3
D2
D1
D0
Ack
by
Master
No Ack
by
Master
1
9
Frame 5
Data Byte from Slave Register ADDR+1
Frame N+4
Data Byte from Slave Register
ADDR+N
D7
D6
D5
D4
D3
D2
D1
D0
1
9
Figure 7-7. I
2
C Sequence of Reading Consecutive Registers
7.3.8.2 I
2
C Bus Control
The LDC3114 cannot drive the I
2
C clock (SCL), that is the device does not support clock stretching. In the
unlikely event where the SCL is stuck LOW, power cycle any device that is holding the SCL to activate its
internal Power-On Reset (POR) circuit. If the LDC is connected to the same power supply as that device, there
will be about 66-ms setup time before the LDC becomes active again. For more information, refer to
. If the data line (SDA) is stuck LOW, the I
2
C controller should send nine clock pulses. The
device that is holding the bus LOW should release the bus sometime within those nine clocks. If not, then power
cycle to clear the bus.
The LDC3114 has built-in monitors to check that the device is currently working. In the unlikely event of a device
fault, the device state will be reset internally, and all the registers will be reset with default settings. For system
robustness, TI recommends to check the value of a modified register periodically to monitor the device status
and reload the register settings, if needed.
7.4 Device Functional Modes
The LDC3114 supports two power modes of operation: a Normal Power Mode for active sampling at 10, 20, 40,
or 80 SPS, and a Low Power Mode for reduced current consumption at 0.625, 1.25, 2.5, or 5 SPS. The device
can also be configured in Normal Power Mode for additional faster sampling rate of 160 SPS or for a continuous
sampling rate. Refer to
Configuring Button or Raw Data Scan Rate
7.4.1 Normal Power Mode
When the LPWRB input pin is set to V
DD
, all enabled channels operate in Normal Power Mode. Each channel
can be enabled independently through
Register EN (Address 0x0C)
. For the electrical specification of Normal
Power Mode Scan Rate, refer to the
SNOSDD0 – DECEMBER 2021
14
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