EFM32WG Datasheet, PDF (425/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

Table 16.6. I²C STATE Values
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Mode
IDLE
WAIT
START
ADDR
ADDRACK
DATA
DATAACK
Value
0
1
2
3
4
5
6
Description
No transmission is being performed by this module.
Waiting for idle. Will send a start condition as soon as the bus is idle.
Start being transmitted
Address being transmitted or has been received
Address ACK/NACK being transmitted or received
Data being transmitted or received
Data ACK/NACK being transmitted or received
Table 16.7. I²C Transmission Status
Bit
BUSY
MASTER
TRANSMITTER
BUSHOLD
NACK
Description
Set whenever there is activity on the bus. Whether or not this module is
responsible for the activity cannot be determined by this byte.
Set when operating as a master. Cleared at all other times.
Set when operating as a transmitter; either a master transmitter or a slave
transmitter. Cleared at all other times
Set when the bus is held by this I²C module because an action is required by
software.
Only valid when bus is held and STATE is ADDRACK or DATAACK. In that case
it is set if a NACK was received. In all other cases, the bit is cleared.
Note
I2Cn_STATE reflects the internal state of the I²C module, and therefore only held constant
as long as the bus is held, i.e. as long as BUSHOLD in I2Cn_STATUS is set.
16.3.9 Slave Operation
The I²C module operates in master mode by default. To enable slave operation, i.e. to allow the device to
be addressed as an I²C slave, the SLAVE bit in I2Cn_CTRL must be set. In this case the slave operates
in a mixed mode, both capable of starting transmissions as a master, and being addressed as a slave.
16.3.9.1 Slave State Machine
The slave state machine is shown in Figure 16.11 (p. 426) . The dotted lines show where I²C-specific
interrupt flags are set. The full-drawn circles show places where interaction may be required by software
to let the transmission proceed.
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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