Hardware Reference
In-Depth Information
Data Bits
Data bit timings are approximately as shown in Figure
12-3
. The SDA line is expected to
stabilize high or low according to the data bit being sent, prior to the SCL line going high.
The receiver clocks in the data on the falling edge of SCL, and the process repeats for the
next data bit. Note that most significant bits are transmitted first.
Figure 12-3.
I2C Data bit transmission
Message Formats
Figure
12-4
displays two example I2C messages that can be used with the MCP23017 chip
(covered in Chapter 2 of
Experimenting with Raspberry Pi
[Apress, 2014]). The simplest
message is the write register request.
Figure 12-4.
Example I2C messages
