Rainbow Electronics MAX6871 User Manual
Page 37
MAX6870/MAX6871
EEPROM-Programmable Hex/Quad
Power-Supply Sequencers/Supervisors with ADC
______________________________________________________________________________________
37
WRITE BYTE FORMAT
S
S
ADDRESS
ADDRESS
7 bits
7 bits
SEND BYTE FORMAT
RECEIVE BYTE FORMAT
WR
WR
ACK
ACK
DATA
DATA
8 bits
8 bits
ACK
P
ACK
P
Data Byte–presets the
internal address pointer.
Data Byte–reads data from
the register commanded by
the last read byte or write
byte transmission. Also
dependent on a send byte.
WRITE WORD FORMAT
S
ADDRESS
WR
ACK
ACK
ACK
ACK
COMMAND
DATA
DATA
P
7 bits
8 bits
8 bits
8 bits
Slave Address–
equivalent to chip-
select line of a 3-
wire interface.
Command Byte–
MSB of the
EEPROM
register being
written.
Data Byte–first byte is the LSB of
the EEPROM address. Second
byte is the actual data.
BLOCK WRITE FORMAT
S
ADDRESS
WR
ACK
COMMAND
ACK
BYTE
COUNT= N
ACK
DATA BYTE
1
ACK
DATA BYTE
...
ACK
DATA BYTE
N
ACK
P
7 bits
8 bits
8 bits
8 bits
8 bits
Slave Address–
equivalent to chip-
select line of a 3-
wire interface.
Command Byte–
prepares device
for block
operation.
Data Byte–data goes into the register set by the
command byte.
BLOCK READ FORMAT
S
ADDRESS
WR
ACK
COMMAND
ACK
SR
ADDRESS
WR
ACK
8 bits
BYTE
COUNT= 16
ACK
DATA BYTE
1
ACK
DATA BYTE
...
ACK
DATA BYTE
N
ACK
P
7 bits
8 bits
7 bits
10h
8 bits
8 bits
8 bits
Slave Address–
equivalent to chip-
select line of a 3-
wire interface.
Command Byte–
prepares device
for block
operation.
Slave Address–
equivalent to chip-
select line of a 3-
wire interface.
Data Byte–data goes into the register set by the
command byte.
S = Start condition.
P = Stop condition.
Shaded = Slave transmission.
SR = Repeated start condition.
Slave Address–
equivalent to chip-
select line of a 3-
wire interface.
Slave Address–
equivalent to chip-
select line of a 3-
wire interface.
S
ADDRESS
WR
ACK
COMMAND
ACK
DATA
ACK
P
7 bits
8 bits
8 bits
Slave Address–
equivalent to chip-
select line of a 3-
wire interface.
Command Byte–
selects register
being written.
Data Byte–data goes into the
register set by the command
byte if the command is below
50h. If the command is 80h,
81h, or 82h, the data byte
presets the LSB of an EEPROM
address.
1
0
0
0
0
1
0
Figure 7. SMBus/I
2
C Protocols