Explore MCP23017 pins, signal names, electrical functions and connection guidance for each package.
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Port B bit 0; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port B bit 1; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port B bit 2; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port B bit 3; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port B bit 4; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port B bit 5; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port B bit 6; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
The current MCP23017 datasheet restricts this terminal to output use. Do not allocate it to a switch or sensor input.
Configure as output LOW and leave open when unused.
GPA7 / GPB7 output-only restriction is specific to MCP23017; do not inherit MCP23S17 input capability.
Powers logic and I/O. Supply, temperature and bus-rate conditions must be considered together.
Use +5 V and 100 nF to VSS10.
Supply and signal reference.
Join controller ground.
Not used on the I²C MCP23017.
Leave unconnected.
This is CS on the different SPI MCP23S17.
Clock for register transfers.
Connect to host SCL and a suitable pull-up to +5 V.
100 kHz example; faster modes require their own voltage and timing conditions.
Open-drain serial data line.
Connect to host SDA and a suitable pull-up to +5 V.
Not used on the I²C MCP23017.
Leave unconnected.
This is SO on the different SPI MCP23S17.
Sets hardware address bit 0; all three LOW select 0x20.
Tie directly to GND in the example.
Do not leave address inputs floating.
Sets hardware address bit 1; all three LOW select 0x20.
Tie directly to GND in the example.
Do not leave address inputs floating.
Sets hardware address bit 2; all three LOW select 0x20.
Tie directly to GND in the example.
Do not leave address inputs floating.
Resets registers and places outputs in the reset state.
Use a 10 kΩ pull-up to +5 V and a controller or reset switch to GND.
Minimum LOW reset pulse is 1 µs.
Configurable polarity and push-pull/open-drain output. May be mirrored with INTA through IOCON.
Leave open in this example; port B interrupts are disabled.
Reports enabled input conditions. GPIO or INTCAP reads clear the associated interrupt as specified.
Use open-drain mode with 10 kΩ pull-up to +5 V and connect host IRQ.
IOCON.ODR = 1 enables open-drain, active-LOW operation.
Port A bit 0; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Connect LED cathode; anode through 1 kΩ to +5 V.
Read GPIO for terminal levels and OLAT for the output latch.
Port A bit 1; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Connect pushbutton to GND; enable input mode and weak pull-up.
Read GPIO for terminal levels and OLAT for the output latch.
Port A bit 2; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port A bit 3; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port A bit 4; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port A bit 5; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
Port A bit 6; IODIR selects input/output, GPPU enables weak pull-up, and interrupt registers control input-change detection.
Leave open with input weak pull-up enabled in this example.
Read GPIO for terminal levels and OLAT for the output latch.
The current MCP23017 datasheet restricts this terminal to output use. Do not allocate it to a switch or sensor input.
Configure as output LOW and leave open when unused.
GPA7 / GPB7 output-only restriction is specific to MCP23017; do not inherit MCP23S17 input capability.
BETA