MAX7326ATG+T Maxim Integrated Products, MAX7326ATG+T Datasheet - Page 9

• Manufacturer Part Number: MAX7326ATG+T
• Description: IC I/O EXPANDER I2C 16B 24TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX7326ATG+T

• Interface: I²C
• Number Of I /o: 16
• Interrupt Output: Yes
• Frequency - Clock: 400kHz
• Voltage - Supply: 1.71 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 24-TQFN Exposed Pad
• Includes: POR
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

A long read sequence (more than 2 bytes) can be used
to poll the expander continuously without the overhead
of resending the slave address. If more than 2 bytes
are read from the expander, the expander repeatedly
returns the 2 bytes of input port data followed by the
transition flags. The inputs are repeatedly resampled
and the transition flags repeatedly reset for each pair of
bytes read. All changes that occur during a long read
sequence are detected and reported.
The MAX7326 includes a 4-bit interrupt mask register
that selects which inputs generate an interrupt upon
change. Each input’s transition flag is set when its input
changes, independent of the interrupt mask register
settings. The interrupt mask register allows the proces-
sor to be interrupted for critical events, while the inputs
and the transition flags can be polled periodically to
detect less-critical events.
The INT output is not reasserted during a read
sequence to avoid recursive reentry into an interrupt
service routine. Instead, if a data change occurs that
would normally cause the INT output to be set, the INT
assertion is delayed until the STOP condition. INT is not
Table 3. MAX7326 Address Map for Outputs O8–O15
PIN CONNECTION
GND
GND
GND
GND
AD2
SDA
SDA
SDA
SDA
SCL
SCL
SCL
SCL
V+
V+
V+
V+
I
2
C Port Expander with 12 Push-Pull Outputs
GND
GND
GND
GND
AD0
SDA
SDA
SDA
SDA
SCL
SCL
SCL
SCL
V+
V+
V+
V+
_______________________________________________________________________________________
A6
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
A5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
DEVICE ADDRESS
A4
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
A3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
A2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
A1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
reasserted upon a STOP condition if the changed input
data is read before the STOP occurs. The INT logic
ensures that unnecessary interrupts are not asserted,
yet data changes are detected and reported no matter
when the change occurs.
The transition-detection logic incorporates a change
flag and an interrupt mask bit for each of the four input
ports. The four change flags can be read through the
serial interface, and the 4-bit interrupt mask is set
through the serial interface.
Each port’s change flag is set when that port’s input
changes, and the change flag remains set even if the
input returns to its original state. The port’s interrupt
mask determines whether a change on that input port
generates an interrupt. Enable interrupts for high-priority
inputs using the interrupt mask. The interrupt allows the
system to respond quickly to changes on these inputs.
Poll the MAX7326 periodically to monitor less-important
inputs. The change flags indicate whether a permanent or
transient change has occurred on any input since the
MAX7326 was last accessed.
A0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
O15
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
O14
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
OUTPUTS POWER-UP DEFAULT
Transition-Detection Masks
O13
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
and 4 Inputs
O12
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
O11
0
1
1
1
0
1
1
1
0
1
1
1
0
1
1
1
O10
0
1
1
1
0
1
1
1
0
1
1
1
0
1
1
1
O9
0
1
1
1
0
1
1
1
0
1
1
1
0
1
1
1
O8
0
1
1
1
0
1
1
1
0
1
1
1
0
1
1
1
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