MAX7365 Maxim, MAX7365 Datasheet - Page 12

• Manufacturer Part Number: MAX7365
• Description: The MAX7365 is an I²C-interfaced peripheral that provides microprocessors with management of up to 56 key switches
• Manufacturer: Maxim

The device operates as a slave that sends and receives
data through an I
interface uses a serial-data line (SDA) and a serial-
clock line (SCL) to achieve bidirectional communication
between master(s) and slave(s). A master (typically a
microcontroller) initiates all data transfers to and from the
device and generates the SCL clock that synchronizes
the data transfer.
face timing details.
The device’s SDA line operates as both an input and an
open-drain output. A pullup resistor, typically 4.7kI, is
required on SDA. The device’s SCL line operates only
as an input. A pullup resistor is required on SCL if there
Figure 1. Two-Wire Serial Interface Timing Details
Figure 2. START and STOP Conditions
SDA
SCL
SDA
SCL
t
HD, STA
CONDITION
START
Figure 1
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CONDITION
2
C-compatible two-wire interface. The
START
S
t
shows the two-wire serial inter-
LOW
Key-Switch Controller with GPIO Ports
t
R
Serial Interface
t
HIGH
t
SU, DAT
t
F
t
HD, DAT
t
SU, STA
1MHz I
START CONDITION
are multiple masters on the two-wire interface, or if the
master in a single-master system has an open-drain SCL
output.
Each transmission consists of a START (S) condition
(Figure
slave address plus R/W bit, a register address byte, one
or more data bytes, and finally, a STOP (P) condition.
Both SCL and SDA remain high when the interface is not
busy. A master signals the beginning of a transmission
with a START condition by transitioning SDA from high
to low while SCL is high. When the master has finished
communicating with the slave, it issues a STOP condition
by transitioning SDA from low to high while SCL is high.
The bus is then free for another transmission.
REPEATED
t
2) sent by a master, followed by the device’s 7-bit
t
HD, STA
R
2
C-Interfaced 8 x 7
START and STOP Condition
t
SU, STO
t
t
F
F, TX
CONDITION
STOP
MAX7365
CONDITION
t
STOP
BUF
P
CONDITION
START