MAX5945 MAXIM [Maxim Integrated Products], MAX5945 Datasheet - Page 19

• Manufacturer Part Number: MAX5945
• Description: Quad Network Power Controller for Power-Over-LAN
• Manufacturer: MAXIM [Maxim Integrated Products]

Figure 5. 2-Wire Serial Interface Timing Details
Figure 6. 3-Wire Serial Interface Timing Details
Figure 7. Start and Stop Conditions
Both SCL and SDA remain high when the interface is
not busy. A master signals the beginning of a transmis-
sion with a START (S) condition by transitioning SDA
from high to low while SCL is high. When the master fin-
SDAIN
SDA/
SCL
SDAIN/SDA
SDAIN
SCL
START
SCL
S
t
HD, STA
t
HD, STA
START CONDITION
START CONDITION
______________________________________________________________________________________
t
LOW
t
LOW
Start and Stop Conditions
t
R
t
R
t
HIGH
t
HIGH
t
SU, DAT
t
SU, DAT
t
F
t
F
Quad Network Power Controller
t
HD, DAT
t
HD, DAT
STOP
P
t
SU, STA
REPEATED START CONDITION
t
SU, STA
REPEATED START CONDITION
ishes communicating with the slave, the master issues
a STOP (P) condition by transitioning SDA from low to
high while SCL is high. The stop condition frees the bus
for another transmission.
Figure 8. Bit Transfer
SDA
SCL
for Power-Over-LAN
t
HD, STA
t
DATA LINE STABLE;
HD, STA
DATA VALID
DATA ALLOWED
CHANGE OF
t
SU, STO
t
SU, STO
CONDITION
CONDITION
STOP
STOP
t
BUF
t
BUF
CONDITION
CONDITION
START
START
19
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