NB3W800L
www.onsemi.com
14
General SMBus Serial Interface Information for NB3W800L
How to Write
• Controller (host) sends a start bit
• Controller (host) sends the write address
• Clock(device) will acknowledge
• Controller (host) sends the beginning byte location = N
• Clock(device) will acknowledge
• Controller (host) sends the byte count = X
• Clock(device) will acknowledge
• Controller (host) starts sending Byte N through Byte
N+X−1
• Clock(device) will acknowledge each byte one at a
time
• Controller (host) sends a Stop bit
Index Block Write Operation
Controller (Host) Clock (Device)
T starT bit
Slave Address
WR WRite
ACK
Beginning Byte = N
ACK
Data Byte Count = X
ACK
Beginning Byte N
X Byte
ACK
O
O O
O O
O
Byte N + X − 1
ACK
P stoP bit
How to Read
• Controller (host) will send a start bit
• Controller (host) sends the write address
• Clock(device) will acknowledge
• Controller (host) sends the beginning byte location = N
• Clock(device) will acknowledge
• Controller (host) will send a separate start bit
• Controller (host) sends the read address
• Clock(device) will acknowledge
• Clock(device) will send the data byte count = X
• Clock(device) sends Byte N+X−1
• Clock(device) sends Byte 0 through Byte X (if X
(H)
was written to Byte 8)
• Controller (host) will need to acknowledge each byte
• Controller (host) will send a not acknowledge bit
• Controller (host) will send a stop bit
Index Block Read Operation
Controller (Host) Clock (Device)
T starT bit
Slave Address
WR WRite
ACK
Beginning Byte = N
ACK
RT Repeat starT
Slave Address
RD ReaD
ACK
Data Byte Count = X
ACK
X Byte
Beginning Byte N
ACK
O
O O
O O
O
Byte N + X - 1
N Not acknowledge
P stoP bit