ina219 datasheet

Frame1Two-WireSlaveAddressByte
(1)
Frame2RegisterPointerByte
1
StartBy
Master
ACKBy
INA219
ACKBy
INA219
1 9 1 9
SDA
SCL
0 0 A3 A2 A1 A0 R/W P7 P6 P5 P4 P3 P2 P1 P0 Stop
¼
NOTE(1):ThevalueoftheSlaveAddressByteisdeterminedbythesettingsoftheA0andA1pins.RefertoTable1.
Frame1SMBusALERTResponseAddressByte Frame2SlaveAddressByte
(1)
StartBy
Master
ACKBy
INA219
From
INA219
NACKBy
Master
StopBy
Master
1 9 1
9
SDA
SCL
ALERT
0 0 0 1 1 0 0 R/
W 1 0 0 A3 A2 A1 A0
0
NOTE(1):ThevalueoftheSlaveAddressByteisdeterminedbythesettingsoftheA0andA1pins.RefertoTable1.
INA219
www.ti.com SBOS448G –AUGUST 2008–REVISED DECEMBER 2015
Figure 17. Timing Diagram for SMBus Alert
Figure 18. Typical Register Pointer Set
8.5.6.1 High-Speed I
2
C Mode
When the bus is idle, both the SDA and SCL lines are pulled high by the pull-up devices. The master generates
a start condition followed by a valid serial byte containing high-speed (HS) master code 00001XXX. This
transmission is made in fast (400 kbps) or standard (100 kbps) (F/S) mode at no more than 400 kbps. The
INA219 does not acknowledge the HS master code, but does recognize it and switches its internal filters to
support 2.56 Mbps operation.
The master then generates a repeated start condition (a repeated start condition has the same timing as the start
condition). After this repeated start condition, the protocol is the same as F/S mode, except that transmission
speeds up to 2.56 Mbps are allowed. Instead of using a stop condition, repeated start conditions should be used
to secure the bus in HS-mode. A stop condition ends the HS-mode and switches all the internal filters of the
INA219 to support the F/S mode. For bus timing, see Bus Timing Diagram Definitions
(1)
and Figure 1.
8.5.6.2 Power-Up Conditions
Power-up conditions apply to a software reset through the RST bit (bit 15) in the Configuration register, or the I
2
C
bus General Call Reset.
(1) Values based on a statistical analysis of a one-time sample of devices. Minimum and maximum values are not ensured and not
production tested.
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