C8051F02X Datasheet, PDF (188/272 Pages) Silicon Laboratories – 8K ISP FLASH MCU Family

C8051F020/1/2/3
18.3.3. Slave Transmitter Mode
Serial data is transmitted on SDA while the serial clock is received on SCL. The SMBus0 interface receives a START
followed by data byte containing the slave address and direction bit. If the received slave address matches the address
held in register SMB0ADR, the SMBus0 interface generates an ACK. SMBus0 will also ACK if the general call
address (0x00) is received and the General Call Address Enable bit (SMB0ADR.0) is set to logic 1. In this case the
data direction bit (R/W) will be logic 1 to indicate a "READ" operation. The SMBus0 interface receives the clock on
SCL and transmits one or more bytes of serial data, waiting for an ACK from the master after each byte. SMBus0
exits slave mode after receiving a STOP condition from the master.
Figure 18.6. Typical Slave Transmitter Sequence
Interrupt
S
SLA
RA
Data Byte
A
Data Byte
NP
Interrupt
Received by SMBus
Interface
Transmitted by
SMBus Interface
Interrupt
Interrupt
S = START
P = STOP
N = NACK
W = WRITE
SLA = Slave Address
18.3.4. Slave Receiver Mode
Serial data is received on SDA while the serial clock is received on SCL. The SMBus0 interface receives a START
followed by data byte containing the slave address and direction bit. If the received slave address matches the address
held in register SMB0ADR, the interface generates an ACK. SMBus0 will also ACK if the general call address
(0x00) is received and the General Call Address Enable bit (SMB0ADR.0) is set to logic 1. In this case the data direc-
tion bit (R/W) will be logic 0 to indicate a "WRITE" operation. The SMBus0 interface receives one or more bytes of
serial data; after each byte is received, the interface transmits an ACK or NACK depending on the state of the AA bit
in SMB0CN. SMBus0 exits Slave Receiver Mode after receiving a STOP condition from the master.
Figure 18.7. Typical Slave Receiver Sequence
Interrupt
S
SLA
WA
Data Byte
A
Data Byte
AP
Interrupt
Received by SMBus
Interface
Transmitted by
SMBus Interface
Interrupt
Interrupt
S = START
P = STOP
A = ACK
R = READ
SLA = Slave Address
188
Rev. 1.4