MAX7326
I2C Port Expander with
12 Push-Pull Outputs and 4 Inputs
Table 1. MAX7319–MAX7329 Family Comparison (continued)
2
I C
INPUT
INPUTS INTERRUPT
MASK
OPEN-
DRAIN
OUTPUTS OUTPUTS
PUSH-
PULL
PART
SLAVE
ADDRESS
CONFIGURATION
4 I/O, 4 output-only versions:
4 open-drain I/O ports with latching transition
detection interrupt and selectable pullups.
MAX7323
110xxxx
Up to 4
—
Up to 4
4
4 push-pull outputs with selectable power-up default
levels.
0100xxx
0111xxx
MAX7328
MAX7329
8 open-drain I/O ports with nonlatching transition
detection interrupt and pullups on all ports.
Up to 8
—
Up to 8
—
When the MAX7326 is read through the serial interface,
the actual logic levels at the ports are read back.
RST Input
The active-low RST input operates as a reset that voids
2
any I C transaction involving the MAX7326 and forcing
The four input ports offer latching transition detection
functionality. All input ports are continuously monitored
for changes. An input change sets 1 of 4 flag bits that
identify the changed input(s). All flags are cleared upon a
subsequent read or write transaction to the MAX7326.
2
the MAX7326 into the I C STOP condition. The reset
action does not clear the interrupt output (INT).
Standby Mode
When the serial interface is idle, the MAX7326 auto-
matically enters standby mode, drawing minimal supply
current.
A latching interrupt output (INT) is programmed to flag
input data changes on the four input ports through an
interrupt mask register. By default, data changes on any
input port force INT to a logic-low. Interrupt output INT and
all transition flags are deasserted when the MAX7326 is
next accessed through the serial interface.
Slave Address, Power-Up Default
Logic Levels, and Input Pullup Selection
Address inputs AD0 and AD2 determine the MAX7326
slave address and select which inputs have pullup
resistors. Pullups are enabled on the input ports in
groups of two (see Table 2).
Internal pullup resistors to V+ are selected by the address
select inputs (AD0 and AD2). Pullups are enabled on the
input ports in groups of two (see Table 2).
2
The MAX7326 slave address is determined on each I C
Initial Power-Up
transmission, regardless of whether the transmission
is actually addressing the MAX7326. The MAX7326
distinguishes whether address inputs AD0 and AD2 are
connected to SDA or SCL instead of fixed logic levels
V+ or GND during this transmission. This means that the
MAX7326 slave address can be configured dynamically in
the application without cycling the device supply.
On power-up, the transition detection logic is reset, and
INT is deasserted. The interrupt mask register is set to
0x3C, enabling the interrupt output for transitions on
all four input ports. The transition flags are cleared to
indicate no data changes. The power-up default states
2
of the 12 push-pull outputs are set according to the I C
slave address selection inputs, AD0 and AD2 (see Tables
2 and 3). Pullups are enabled on the input port in groups
of two (see Table 2).
On initial power-up, the MAX7326 cannot decode address
inputs AD0 and AD2 fully until the first I C transmission.
This is important because the address selection is used to
determine the power-up logic state (output low or I/O high),
and whether pullups are enabled. However, at power-up,
2
Power-On Reset (POR)
The MAX7326 contains an integral POR circuit that
ensures all registers are reset to a known state on
2
the I C SDA and SCL bus interface lines are high imped-
ance at the pins of every device (master or slave) connect-
ed to the bus, including the MAX7326. This is guaranteed
as part of the I C specification. Therefore, when address
power-up. When V+ rises above V
POR circuit releases the registers and 2-wire interface
for normal operation. When V+ drops below V , the
(1.6V max), the
POR
2
POR
inputs AD0 and AD2 are connected to SDA or SCL during
power-up, they appear to be connected to V+. The port
MAX7326 resets all output register contents to the POR
defaults (Tables 2 and 3).
Maxim Integrated
│ 7
www.maximintegrated.com
5秒后页面跳转
一文带你了解?DB3二极管好坏判断、参数信息、替代推荐
LM358DR数据手册：引脚说明、电气参数及替换型号推荐
OP07CP数据手册解读：引脚信息、电子参数
TIP42C资料手册解读：参数分析、产品特性
微信公众号
抖音公众号
浙公网安备 33010502006866号 浙ICP备10014259号-119
营业执照ICP证
数据手册
如果您发现信息不准确，
