Rev. 0.5 203
C8051F340/1/2/3/4/5/6/7
Tabl e 17.3. Sources for Hardware Changes to SMB0CN

Bit Set by Hardware When: Cleared by Hardware When:

MASTER A START is generated. A STOP is generated.
Arbitration is lost.
TXMODE
START is generated.
SMB0DAT is written before the start of an
SMBus frame.
A START is detected.
Arbitration is lost.
SMB0DAT is not written before the
start of an SMBus frame.
STA A START followed by an address byte is
received. Must be cleared by software.
STO A STOP is detected while addressed as a
slave.
Arbitration is lost due to a detected STOP.
A pending STOP is generated.
ACKRQ A byte has been received and an ACK
response value is needed. After each ACK cycle.
ARBLOST
A repeated START is detected as a MASTER
when STA is low (unwanted repeated START).
SCL is sensed low while attempting to gener-
ate a STOP or repeated START condition.
SDA is sensed low while transmitting a ‘1’
(excluding ACK bits).
Each time SI is cleared.
ACK The incoming ACK value is low (ACKNOWL-
EDGE). The incoming ACK value is high (NOT
ACKNOWLEDGE).
SI
A START has been generated.
Lost arbitration.
A byte has been transmitted and an ACK/
NACK received.
A byte has been received.
A START or repeated START followed by a
slave address + R/W has been received.
A STOP has been received.
Must be cleared by software.