Chapter 2. API Reference
Fig. 5: I2C command link - master write example
a) Start bit - i2c_master_start()
b) Slave address - i2c_master_write_byte(). The single byte address is provided as an argument
of this function call.
c) Data - One or more bytes as an argument of i2c_master_write()
d) Stop bit - i2c_master_stop()
Both functions i2c_master_write_byte() and i2c_master_write() have an addi-
tional argument specifying whether the master should ensure that it has received the ACK bit.
2. Trigger the execution of the command link by I2C controller by calling i2c_master_cmd_begin().
Once the execution is triggered, the command link cannot be modified.
3. After the commands are transmitted, release the resources used by the command link by calling
i2c_cmd_link_delete().
Master Read The example below shows how to build a command link for an I2C master to read n bytes from a
slave.
Fig. 6: I2C command link - master read example
Compared to writing data, the command link is populated in Step 4 not with i2c_master_write... func-
tions but with i2c_master_read_byte() and / or i2c_master_read(). Also, the last read in Step 5 is
configured so that the master does not provide the ACK bit.
Espressif Systems 283
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