MAX14578E_12 Datasheet, PDF (17/23 Pages) Maxim Integrated Products – USB Battery Charger Detectors

MAX14578E/MAX14578AE
USB Battery Charger Detectors
I²C Serial Interface (MAX14578E)
Serial Addressing
The MAX14578E operates as a slave device that sends
and receives data through an I²C-compatible 2-wire
interface. The interface uses a serial-data line (SDA) and
a serial-clock line (SCL) to achieve bidirectional commu-
nication between master(s) and slave(s). A master (typi-
cally a microcontroller) initiates all data transfers to and
from the MAX14578E and generates the SCL clock that
synchronizes the data transfer. The SDA line operates as
both an input and an open-drain output. A pullup resis-
tor is required on SDA. The SCL line operates only as an
input. A pullup resistor is required on SCL if there are
multiple masters on the 2-wire interface, or if the master
in a single-master system has an open-drain SCL output.
Each transmission consists of a START condition (Figure
4) sent by a master, followed by the MAX14578E 7-bit
slave address plus a R/W bit, a register address byte,
one or more data bytes, and finally a STOP condition.
START and STOP Conditions
Both SCL and SDA remain high when the interface is not
busy. A master signals the beginning of a transmission
with a START (S) condition by transitioning SDA from
high to low while SCL is high (see Figure 5). When the
master has finished communicating with the slave, it
issues a STOP (P) condition by transitioning SDA from
low to high while SCL is high. The bus is then free for
another transmission.
SDA
tSU:DAT
tLOW
SCL
t_HD:STA
tHIGH
tR
START
CONDITION
Figure 4. I²C Interface Timing Details
tHD:DAT
tSU:STA
tR
tHD:STA
REPEATED
START CONDITION
tBUF
tSU:STO
STOP
START
CONDITION CONDITION
SDA
SCL
S
START
CONDITION
Figure 5. START and STOP Conditions
P
STOP
CONDITION
Maxim Integrated
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