MAX7300AAI Ver la hoja de datos (PDF) - Maxim Integrated
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componentes Descripción
Fabricante
MAX7300AAI Datasheet PDF : 20 Pages
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2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port I/O Expander
P4 TO P31
CONFIGURATION
GPIO
GPIO DATA
R/W
8
AD0
ADDRESS
AD1
MATCHER
7
8
PORT CHANGE
DETECTOR
PORT REGISTERS
MASK REGISTER
CONFIGURATION
REGISTERS
DATA CE R/W
8
COMMAND
REGISTER DECODE
8
DATA BYTE
COMMAND BYTE
D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15
7
7-BIT DEVICE ADDRESS R/W
SDA
SLAVE ADDRESS BYTE
SCL
TO/FROM DATA REGISTERS
DATA BYTE
TO COMMAND REGISTERS
COMMAND BYTE
Figure 1. MAX7300 Functional Diagram
MAX7300 is the recipient. When the MAX7300 is trans-
mitting to the master, the master generates the
acknowledge bit since the master is the recipient.
Slave Address
The MAX7300 has a 7-bit-long slave address (Figure 6).
The eighth bit following the 7-bit slave address is the
R/ W bit. It is low for a write command and high for a
read command.
The first 3 bits (MSBs) of the MAX7300 slave address
are always 100. Slave address bits A3, A2, A1, and A0
are selected by the address inputs, AD1 and AD0.
These two input pins can be connected to GND, V+,
SDA, or SCL. The MAX7300 has 16 possible slave
addresses (Table 3), and therefore a maximum of 16
MAX7300 devices can share the same interface.
Message Format for Writing
the MAX7300
A write to the MAX7300 comprises the transmission of
the MAX7300’s slave address with the R/ W bit set to
zero, followed by at least 1 byte of information. The first
byte of information is the command byte. The com-
mand byte determines which register of the MAX7300
is to be written by the next byte, if received. If a STOP
condition is detected after the command byte is
received, then the MAX7300 takes no further action
(Figure 7) beyond storing the command byte.
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