Max7315, Functional overview, Pin description – Rainbow Electronics MAX7315 User Manual

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MAX7315

Functional Overview

The MAX7315 is a general-purpose input/output (GPIO)
peripheral that provides eight I/O ports, P0–P7, con-
trolled through an I

C-compatible serial interface. A 9th

output-only port, INT/O8, can be configured as an inter-
rupt output or as a general-purpose output port. All out-
put ports sink loads up to 50mA connected to external
supplies up to 5.5V, independent of the MAX7315’s

supply voltage. The MAX7315 is rated for a ground cur-
rent of 190mA, allowing all nine outputs to sink 20mA at
the same time. Figure 1 shows the output structure of
the MAX7315. The ports default to inputs on power-up.

Port Inputs and Transition Detection

An input ports register reflects the incoming logic levels
of the port pins, regardless of whether the pin is
defined as an input or an output. Reading the input

8-Port I/O Expander with LED Intensity
Control and Interrupt

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PIN

QSOP/TSSOP

QFN

NAME

FUNCTION

1, 2, 3

15, 16, 1

AD0, AD1,

AD2

Address Inputs. Sets device slave address. Connect to either GND, V+,
SCL, or SDA to give 64 logic combinations. See Table 1.

4–7, 9–12

2–5, 7–10

P0–P7

Input/Output Ports. P0–P7 are open-drain I/Os rated at 5.5V, 50mA.

GND

Ground. Do not sink more than 190mA into the GND pin.

INT/O8

Output Port. Open-drain output rated at 7.0V, 50mA. Configurable as
interrupt output or general-purpose output.

SCL

C-Compatible Serial Clock Input

SDA

C-Compatible Serial Data I/O

V+

Positive Supply Voltage. Bypass V+ to GND with a 0.047µF ceramic
capacitor

—

PAD

Exposed pad

Exposed Pad on Package Underside. Connect to GND.

Pin Description

Figure 1. Simplified Schematic of I/O Ports

DATA FROM

SHIFT REGISTER

DATA FROM

SHIFT REGISTER

WRITE

CONFIGURATION

PULSE

WRITE PULSE

READ PULSE

CONFIGURATION

INPUT PORT

OUTPUT

PORT

OUTPUT PORT
REGISTER DATA

I/O PIN

GND

INPUT PORT
REGISTER DATA

TO INT