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This document explains about the hardware and software setup, which is required to interface a joystick with the EV-COG-AD3029LZ using MCP23S17 as an interfacing I/O expander chip. The entire setup is made simple with the use of AD-GEAR-DISPLAY1Z, which contains the joystick and the expander IC.

The hardware details cover the COG jumper settings and also the pin mapping between the joystick, MCP23S17 expander and the EV-COG-AD3029LZ. The software details cover the software development kit required and the software architecture of the code base written to interface the joystick with the EV-COG-AD3029LZ.

Boards and Accessories required

a.) EV-COG-AD3029LZ (left) b.) AD-GEAR-DISPLAY1Z (right)

Hardware interface

This section contains hardware related information about AD-GEAR-DISPLAY1Z and the EV-COG-AD3029-LZ. Links are provided to the WiKi page of the target COG-AD3029-LZ, the Schematics, BOMs and technical documentations at the end of this page.

Connection Diagram

* The joystick and the I/O expander-MCP23s17 are embedded on the AD-GEAR-DISPLAY1Z.

Board Interface

  1. Connect the AD-GEAR-DISPLAY1Z via it’s Cog connectors to the EV-COG-AD3029LZ’s expansion connectors.

Pin Connection

EV-COG-AD3029LZ pins MCP23S17 pins Joystick
GPIO34 / SPI1_CS2 CS_N -
- GPA0 SW1
- GPA1 SW2
- GPA2 SW3
- GPA3 SW4
- GPA4 SW5

* A0, A1 and A2 of the I/O expander are connected to the ground.

* RESET_N of the I/O expander is connected to EXT_VDD_OUT of the COG board.

Software Details

This section contains software related information about AD-GEAR-DISPLAY1Z and the EV-COG-AD3029-LZ and the application. Links are provided to the user guides, BSPs, software tool chains and the example project at the end of this page.

Application files

The example project provided consists mainly of the following,

  1. mcp23s17_3.c
  2. mcp23s17.h
  3. SPI_PE.h
  4. adi_spi_pe.h
  5. IAR project files( *.eww, *.ewt, *.ewt)
  • The application uses the ADuCM302x-Rel 2.0.0 driver BSP for IAR.
  • IAR Embedded Workbench 7.60.1 or higher is advised to be used.

Application flow

* All the APIs for using the I/O expander is within the mcp23s17_3.c with supporting definitions found in SPI_PE.h and adi_spi_pe.h. A separate driver file to use the I/O expander is yet to be created.

IDE Setup and example application

This section covers the various steps involved in getting the joystick_example application code to run on EV-COG-AD3029LZ after the hardware setup is done.

Following are the steps involved,

  1. Download and install IAR Embedded Workbench 7.60.1 or higher.
  2. Download the joystick_example project from
  3. The joystick_example project is also available on Bitbucket.
  4. Import the source into IAR workspace and run the application software to generate interrupts by joystick press.
resources/eval/user-guides/ev-cog-ad3029lz/example_project/joystick_example.1609707327.txt.gz · Last modified: 03 Jan 2021 21:55 by Robin Getz