C8051F340/1/2/3/4/5/6/7

Table 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.

 

 

 

START is generated.

A START is detected.

TXMODE

SMB0DAT is written before the start of an

Arbitration is lost.

SMBus frame.

SMB0DAT is not written before the

 

 

 

start of an SMBus frame.

STA

A START followed by an address byte is

Must be cleared by software.

received.

 

 

 

STO

A STOP is detected while addressed as a

A pending STOP is generated.

slave.

 

 

Arbitration is lost due to a detected STOP.

 

ACKRQ

A byte has been received and an ACK

After each ACK cycle.

response value is needed.

 

 

 

 

A repeated START is detected as a MASTER

Each time SI is cleared.

 

when STA is low (unwanted repeated START).

 

ARBLOST

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).

 

ACK

The incoming ACK value is low (ACKNOWL-

The incoming ACK value is high (NOT

EDGE).

ACKNOWLEDGE).

 

 

A START has been generated.

Must be cleared by software.

 

Lost arbitration.

 

 

A byte has been transmitted and an ACK/

 

SI

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.

 

Rev. 0.5

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Silicon Laboratories C8051F343 Sources for Hardware Changes to SMB0CN, Bit Set by Hardware When Cleared by Hardware When