Rainbow Electronics MAX6652 - Manual (Page 11)

MAX6652
Temperature Sensor and System Monitor
in a 10-Pin µMAX
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SMBCLK
A B C D E F G H I J K
SMBDATA
t SU:STA t HD:STA
t LOW t HIGH
t SU:DAT t HD:DAT t SU:STO t BUF
A = START CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS CLOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE
E = SLAVE PULLS SMBDATA LINE LOW
L M
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO SLAVE
H = LSB OF DATA CLOCKED INTO SLAVE
I = MASTER PULLS DATA LINE LOW J = ACKNOWLEDGE CLOCKED INTO SLAVE
K = ACKNOWLEDGE CLOCK PULSE
L = STOP CONDITION
M = NEW START CONDITION
Figure 3. I 2 C/SMBus Write Timing Diagram
Write Byte Format
Read Byte Format
Send Byte Format Receive Byte Format
Slave Address: equiva-
lent to chip-select line of
a 3-wire interface Command Byte: selects which
register you are writing to Data Byte: data goes into the register
set by the co mma nd byte ( to se t
thresholds, configuration masks, and
sampling rate)
Slave Address: equiva-
lent to chip-select line Command Byte: selects
which register you are
reading from Slave Address: repeated
due to change in data-
flow direction Data Byte: reads from
the register set by the
command byte
Data Byte: writes data to the
register commanded by the
last read byte or write byte
transmission Data Byte: reads data from
the register commanded
by the last read byte or
write byte transmission;
also used for SMBus alert
response return address
S = Start condition
P = Stop condition Shaded = Slave transmission
A = Not acknowledged
ACK
7 bits
ADDRESS ACK
8 bits
DATA ACK P
8 bits
S COMMAND WR
ACK
7 bits
ADDRESS ACK S ACK
8 bits
DATA
7 bits
ADDRESS RD
8 bits
P S COMMAND A WR
ACK
7 bits
ADDRESS
8 bits
COMMAND ACK P S WR ACK
7 bits
ADDRESS RD
8 bits
DATA P S A
Figure 2. I 2 C/SMBus Protocols