C8051F581-IMR Silicon Labs, C8051F581-IMR Datasheet - Page 250

• Manufacturer Part Number: C8051F581-IMR
• Description: 8-bit Microcontrollers - MCU 50MIPS 128kB 8kB SPI
• Manufacturer: Silicon Labs

Specifications of C8051F581-IMR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

C8051F58x/F59x
23.5.3. Write Sequence (Slave)
During a write sequence, an SMBus master writes data to a slave device. The slave in this transfer will be
a receiver during the address byte, and a receiver during all data bytes. When slave events are enabled
(INH = 0), the interface enters Slave Receiver Mode when a START followed by a slave address and direc-
tion bit (WRITE in this case) is received. Upon entering Slave Receiver Mode, an interrupt is generated
and the ACKRQ bit is set. The software must respond to the received slave address with an ACK, or ignore
the received slave address with a NACK.
If the received slave address is ignored, slave interrupts will be inhibited until the next START is detected.
If the received slave address is acknowledged, zero or more data bytes are received. Software must write
the ACK bit at that time to ACK or NACK the received byte.
The interface exits Slave Receiver Mode after receiving a STOP. Note that the interface will switch to Slave
Transmitter Mode if SMB0DAT is written while an active Slave Receiver. Figure 23.7 shows a typical slave
write sequence. Two received data bytes are shown, though any number of bytes may be received. Notice
that the ‘data byte transferred’ interrupts occur before the ACK in this mode.
250
S
Received by SMBus
Interface
Transmitted by
SMBus Interface
SLA
Figure 23.7. Typical Slave Write Sequence
W
A
Data Byte
Rev. 1.2
Interrupts
A
S = START
P = STOP
A = ACK
W = WRITE
SLA = Slave Address
Data Byte
A
P