Data Sheet

ISM14585-L35 Specification
DOC-DS-14585-201807-3.0
Confidential Inventek Systems
Page 42
9.7.6.1 SLAVE MODE OPERATION
This section includes the following procedures:
• Initial Configuration
• Slave-Transmitter Operation for a Single Byte
• Slave-Receiver Operation for a Single Byte
• Slave-Transfer Operation for Bulk Transfers
Initial Configuration
To use the I2C Controller as a slave, perform the following steps:
1. Disable the I2C Controller by writing a ‘0’ to bit 0 of the I2C_ENABLE register.
2. Write to the I2C_SAR register (bits 9:0) to set the slave address. This is the
address to which the I2C Controller responds.
3. Write to the I2C_CON register to specify which type of addressing is supported
(7-bit or 10-bit by setting bit 3). Enable the I2C Controller in slave-only mode by
writing a ‘0’ into bit 6 (I2C_SLAVE_DISABLE) and a ‘0’ to bit 0
(MASTER_MODE).
a. Note: Slaves and masters do not have to be programmed with the same
type of addressing 7-bit or 10-bit address. For instance, a slave can be
programmed with 7-bit addressing and a master with 10-bit addressing,
and vice versa.
4. Enable the I2C Controller by writing a ‘1’ in bit 0 of the I2C_ENABLE register.
a. Note: Depending on the reset values chosen, steps 2 and 3 may not be
necessary because the reset values can be configured. For instance, if the
device is only going to be a master, there would be no need to set the
slave address because you can configure I2C Controller to have the slave
disabled after reset and to enable the master after reset. The values
stored are static and do not need to be reprogrammed if the I2C Controller
is disabled.
Slave-Transmitter Operation for a Single Byte
When another I2C master device on the bus addresses the I2C Controller and requests
data, the I2C Controller acts as a slave-transmitter and the following steps occur:
1. The other I2C master device initiates an I2C transfer with an address that
matches the slave address in the I2C_SAR register of the I2C Controller.
2. The I2C Controller acknowledges the sent address and recognizes the direction
of the transfer to indicate that it is acting as a slave-transmitter.