I2CIO16-DB25

Features

• 16-bit Digital I/O card
  • MCP23017 16-bit I2C I/O Expander
  • Strong library support for all major microprocessors for MCP23017
• I2C Interface - Two Wire Interface
  • Can run at 400 KHz or faster
• I/O Connector is inexpensive/standard DB-25 female
  • Easy/quick to connect/disconnect
  • 16 Digital I/O lines
  • (3) Power, (3) Ground
• Host connectors
  • Daisy-chain I2C connector
  • Address select jumper
  • I2C base address = 0x20
  • Jumpers allow card to be put at any I2C address in range 0x20-0x27
  • Expandable I2C via I2C-RPT or I2C-RPT-08 - I2C Repeater
    • Maximal example
      • 8 I2C-RPT-08 Multiplexers
      • 8 cards per multiplexer
      • 16 I/O connections per card
      • 1,024 I/O
  • I2C Termination jumpers for end of I2C chain
• Power can be 3.3V or 5V
• Easy mounting options
  • Front panel cut-out
  • 6-32 Mounting holes
  • Boards can be stacked with 6-32 standoffs

Connectors

J1 - DB-25 I/O Connector

• DB-25 female pinout from the front of the card/connector

• Pins 1, 2, 14 are connected to Power
• Pins 12, 13, 25 are connected to Ground
• Pins 11, 15, 24 are not used

J2 - I2C Termination

• Two of two position headers
• Install headers in each position to terminate I2C line
• There should only be one set of I2C termination jumpers and termination should be at the end of the I2C daisy-chain
• Side-by-side horizontal orientation (opposite of Address jumpers orientation)

J3 - I2C

• Connector is 2x5 of 0.1" header
• Intended to be used for I2C daisy-chain of 4-pin cabling
• Power can be attached to the connector or power can be provided to the card via the J1 power connector
• May still want to connect ground

1. INT
2. SCL
3. SDA
4. VCC
5. GND

J4 - Address Select

• Sets the I2C offset address of the card
• Install jumper for Ax = 0, remove jumper for Ax = 1
• Three bit address A1, A2

1. A0
2. A1
3. A2

I2C Address	J4(A2)	J4(A1)	J4(A0)
0x0	In	In	In
0x1	In	In	Out
0x2	In	Out	In
0x3	In	Out	Out
0x4	Out	In	In
0x5	Out	In	Out
0x6	Out	Out	In
0x7	Out	Out	Out

• Jumper orientation

Rear Side Marking

MCP23017 Drivers

There are quite a I2C drivers for every major microcontroller (Arduino, Raspberry Pi, BeagleBone, etc).

Arduino Drivers

• Land Boards Arduino Driver Code/Example Software for the PROTO16-I2C Card
• Adafruit MCP23017 Arduino Driver

Raspberry Pi Drivers

• Raspberry Pi WiringPi Driver

Raspberry Pi Pico

MMBASIC

• I2CIO16-DB25.bas code to bounce an LED
  • Runs on PiPicoMite01 or PiPicoMite02 card

BeagleBone Black Drivers

• BeagleBone Black Example

ESP32 MicroPython Drivers

• MicroPython MCP23017 driver
• MicroPython Example code

PyBoard MicroPython Drivers

• MicroPython MCP23017 driver
• MicroPython Example

Linux Drivers

• Linux Driver source code

Mechanicals

Factory Acceptance Tests

Setup

• Unit Under Test (UUT)
• Runs on PiPicoMite02 Based Test Station
  • PiPicoMite02
  • LED-32 card
    • Uses 16 LEDs for the digital I/O and 3 for power

• I2C cable from PiPicoMite02 Based Test Station to UUT
• Cables/Adapter
  • DB25RIBBON with male connector plugged into UUT

Ribbon Cable Wiring

• Cable between LED-32 and DB25RIBBON

J1	DB25	I2CIO16	LED-32		J1	DB25	I2CIO16	LED-32
25	1	GND			26		N/C
23	2	GND			24	14	GND
21	3	GP0	D15		22	15	N/C
19	4	GP1	D14		20	16	GP15	D24
17	5	GP2	D13		18	17	GP14	D25
15	6	GP3	D12		16	18	GP13	D26
13	7	GP4	D11		14	19	GP12	D27
11	8	GP5	D10		12	20	GP11	D28
9	9	GP6	D9		10	21	GP10	D29
7	10	GP7	D8		8	22	GP9	D30
5	11	N/C			6	23	GP8	D31
3	12	+3.3V	D0		4	24	N/C
1	13	+3.3V	D1		2	25	+3.3V	D3

Run Test Code

• Runs I2CIO16-DB25.bas code
• Run on PiPicoMite02 Based Test Station

chdir "/lbcards/GPIO16"
load "I2CIO16-DB25.bas"
run

• Result
  • Code bounces LED
  • 3 Power LEDs should be constantly be lit

Issues

Rev 1

• No issues
• Card is fully functional

I2CIO16-DB25 Rev 1 Assembly Sheet

• I2CIO16-DB25 Rev 1 Assembly Sheet