20.4.2 SMB0CN0: SMBus 0 Control
Bit
7
6
5
4
3
2
1
0
Name
MASTER
TXMODE
STA
STO
ACKRQ
ARBLOST
ACK
SI
Access
R
R
RW
RW
R
R
RW
RW
Reset
0
0
0
0
0
0
0
0
SFR Page = 0x0; SFR Address: 0xC0 (bit-addressable)
Bit
Name
Reset
Access
Description
7
MASTER
0
R
SMBus Master/Slave Indicator.
This read-only bit indicates when the SMBus is operating as a master.
Value
Name
Description
0
SLAVE
SMBus operating in slave mode.
1
MASTER
SMBus operating in master mode.
6
TXMODE
0
R
SMBus Transmit Mode Indicator.
This read-only bit indicates when the SMBus is operating as a transmitter.
Value
Name
Description
0
RECEIVER
SMBus in Receiver Mode.
1
TRANSMITTER
SMBus in Transmitter Mode.
5
STA
0
RW
SMBus Start Flag.
When reading STA, a '1' indicates that a start or repeated start condition was detected on the bus.
Writing a '1' to the STA bit initiates a start or repeated start on the bus.
4
STO
0
RW
SMBus Stop Flag.
When reading STO, a '1' indicates that a stop condition was detected on the bus (in slave mode) or is pending (in master
mode).
When acting as a master, writing a '1' to the STO bit initiates a stop condition on the bus. This bit is cleared by hardware.
3
ACKRQ
0
R
SMBus Acknowledge Request.
Value
Name
Description
0
NOT_SET
No ACK requested.
1
REQUESTED
ACK requested.
2
ARBLOST 0
R
SMBus Arbitration Lost Indicator.
Value
Name
Description
0
NOT_SET
No arbitration error.
1
ERROR
Arbitration error occurred.
1
ACK
0
RW
SMBus Acknowledge.
When read as a master, the ACK bit indicates whether an ACK (1) or NACK (0) is received during the most recent byte
transfer.
As a slave, this bit should be written to send an ACK (1) or NACK (0) to a master request. Note that the logic level of the
ACK bit on the SMBus interface is inverted from the logic of the register ACK bit.
EFM8SB2 Reference Manual
System Management Bus / I2C (SMB0)
silabs.com
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