CMS32L051 User Manual |Chapter 14 Serial interface IICA
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14.5.16 Communication operation
The following 3 running steps are represented here by a flowchart.
(1) Master operation of a single-master system
The flowchart used as a master device in a single master system is shown below.
This process is broadly divided into initialization and communication processing. Performs the
Initial Setup section at startup and, if communication with the slave is required, the Communication
Handling section after the preparation required for communication.
.
(2) Master operation of multi-master systems
In a multi-master system of the I
2
C-bus, it is not possible to determine whether the stage bus
participating in the communication is in the release state or in the use state according to the
specifications of the I
2
C-bus alone. Here, if the data and clock are high within a certain period of time (1
frame), the bus participates in the communication as a release state. This process is broadly divided
into Initialization, Communication Waiting, and Communication Processing. The processing that was
designated as a slave due to arbitration failure is omitted here, and only indicates the processing used
as the master device. Join the bus after performing the Initial Setup section at startup, and then wait
for the communication request of the master device or the designation of the slave device through
Communication Wait. The actual communication is carried out in the Communication Processing
part, which supports arbitration with other master devices in addition to data transmission and reception
with the slave device.
(3) Slave operation
An example of a slave device used as an I
2
C-bus is shown below.
When used as a slave, it starts operating by interrupt. Perform the Initialization section at startup
and then wait for the INTIICAn interrupt to occur via Communication Wait. If an INTIICAn interruption
occurs, the communication status is determined and the flag is passed to the main processing
department.
By checking each flag, the required Communication processing is performed.
Remark n=0
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