Detailed Description
MAX7324–MAX7327 Family Comparison
The MAX7324–MAX7327 family consists of four pin-
compatible, 16-port expanders that integrate the func-
tion of the MAX7320 and one of either the MAX7319,
MAX7321, MAX7322, or MAX7323.
Functional Overview
The MAX7324 is a general-purpose port expander
operating from a +1.71V to +5.5V supply with eight
push-pull outputs and eight CMOS input ports that are
overvoltage protected to +6V.
The MAX7324 is set to two of 32 I
2
C slave addresses
(see Tables 2 and 3) using address select inputs AD0
and AD2, and is accessed over an I
2
C serial interface
up to 400kHz. The eight outputs and eight inputs have
different slave addresses. The eight push-pull outputs
have the 101xxxx addresses and the eight inputs have
the adresses with 110xxxx. The RST input clears the
serial interface in case of a bus lockup, terminating any
serial transaction to or from the MAX7324.
The input ports offer latching transition detection fea-
ture. All input ports are continuously monitored for
changes. An input change sets 1 of 8 flag bits that
identify the changed input(s). All flags are cleared upon
a subsequent read or write transaction to the MAX7324.
MAX7324
I
2
C Port Expander with Eight Push-Pull Outputs
and Eight Inputs
_______________________________________________________________________________________ 5
8 Yes — 8
8 inputs and 8 push-pull outputs version:
8 input ports with programmable latching transition
detection interrupt and selectable pullups.
8 push-pull outputs with selectable default logic
levels.
Offers maximum versatility for automatic input
monitoring. An interrupt mask selects which inputs
cause an interrupt on transitions, and transition flags
— Up to 8 8
8 I/O and 8 push-pull outputs version:
8 open-drain I/O ports with latching transition
detection interrupt and selectable pullups.
8 push-pull outputs with selectable default logic
levels.
Open-drain outputs can level shift the logic-high
state to a higher or lower voltage than V+ using
external pullup resistors, but pullups draw current
when output is low. Any open-drain port can be used
as an input by setting the open-drain output to logic-
high. Transition flags identify which open-drain port
inputs have changed (even if only for a transient)
since the ports were last read.
