SWLEDX8-I2C

Features

• 16-Bit Digital I/O card with a small form factor
  • MCP23017 I/O Expander
  • I2C interface
• Card can be used standalone or stacked together with the SWLEDX8 card
• I2C Daisy-Chain (In/Out) connectors
• (3) I2C Address select jumpers for up to 8 devices per I2C bus
• SCL/SDA termination jumpers
• 2x10 pins Digital I/O Header
  • 16 digital pins
  • 2 power, 2 ground pins
• 59mmx38mm
• (4) #4-40 mounting holes
• Software Drivers

Build Options

• There are a number of options for using the card
  • Stacked option with SWLEDX8 card
  • Small footprint option
  • Low height/profile option

Stacked option with SWLEDX8 card

• SWLEDX8 card mounts above this card
• Pins can be directly mounted to both cards or male/female connector pairs can be used

Small footprint option

Low height/profile option

Rear Side Marking

Connectors

• Connectors are as follows

P1 - GPIO Pins

Connections to SWLEDX8 Card

• When paired with SWLEDX8
  • MCP23017 Port A connects to SWITCHES 0-7 on SWLEDX8
  • MCP23017 Port B connects to LEDs 0-7 on SWLEDX8
• Board Rev 2 reverses bit order for byte transfers can be used

P2 - I2C Interface

• 2X5 header
• Pinout

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

P3 - I2C Terminators / I2C Address Offset Jumpers

• Install left 2 jumpers to terminate I2C bus
  • Typically, the "last" card in a chain
• Install right 3 jumpers for I2C base address offset in range 0x20 (all installed) to 0x27 (all removed)

Drivers / Software Examples

• Any MCP23017 library should work with this card
• Here's our tested code

Arduino

• LandBoards MCP23017
  • pinMode(uint8_t bit, uint8_t value) - Set bits 0-7=Input, 8-15=Output
  • readGPIOA() - Read the 8 Switches
  • writeOLATB(uint8_t baData) _ Write the 8 LEDs
  • digitalRead(uint8_t bit) - read a single Switch (bit=0-7)
  • digitalWrite(uint8_t bit, uint8_t wrVal) - write a single LED (nit=8-15)
• SWLEDX8_01.ino - Read 8 Switches, Write 8 LEDs
  • Example running on Arduino in a Box

MicroPython Drivers

ESP32 MicroPython Driver

• ESP32 MicroPython Driver

PyBoard MicroPython Driver

• PyBoard MicroPython Driver

CircuitPython

• SWLEDX8.py = Control the card

Raspberry Pi Pico

MMBASIC

• SWLEDX8-01.bas - Read 8x switches, write 8x LEDs
• MMBASIC Example Code - Bounce a bit across the 16-bits (not for use with SWLEDX8 card)
• swledx8-03.bas - Write alternating pattern to LEDs then read/write switches to LEDs

I2C VHDL Code

• I2C VHDL Code

Mechanicals

Versions

Rev 2

• Not functionally the same as Rev X1
  • Flips the data bits to match the SWLEDX8 card
    • Programs can read/write in bytes (no shuffling of bits needed)
• Change resistors from SMT (0805) to through hole (1/8W)
• Adds silkscreen Front/Rear
• Added test block to rear
• Moves "Rev 2" silkscreen to rear

Rev X1

• Words, no issues

Assembly Sheet

• SWLEDX8-I2C Rev 2 Assembly Sheet
• SWLEDX8-I2C Rev X1 Assembly Sheet