Microchip ATMXT448UD Bruksanvisning


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2019 Microchip Technology Inc. DS00003084A-page 1
TABLE OF CONTENTS
1.0 Introduction ................................................................................................................................................................. 1
1.1 SAMA5D3 Xplained Board ............................................................................................................................... 2
1.2 SAM Boot Assistance (SAM-BA) ...................................................................................................................... 2
1.3 Putty Terminal Program .................................................................................................................................... 3
1.4 Github Repository – maXTouch_linux .............................................................................................................. 4
2.0 Building the source and setting up the tools ................................................................................................................ 5
2.1 Device Tree Files .............................................................................................................................................. 5
2.1.1 at91-sama5d3_xplained_dm_pda4.dtsi ................................................................................................ 5
2.1.2 at91-sama5d3_xplained_pda4.dts ....................................................................................................... 5
2.2 Configuring the Kernel Options ......................................................................................................................... 5
2.3 Loading the Touch Driver as a Module ............................................................................................................. 6
2.4 Building the Kernel ............................................................................................................................................ 6
2.5 Modifying the U-boot-env.txt File ...................................................................................................................... 7
2.6 Programming the SAMA5D3 Xplained Board ................................................................................................... 8
3.0 maXTouch Linux Driver ............................................................................................................................................... 9
3.1 I2C Driver – atmel_mxt_ts.c .............................................................................................................................. 9
3.2 Object-based Protocol ...................................................................................................................................... 9
3.3 Power Up and Reset ......................................................................................................................................... 9
3.4 Downloading the Configuration ......................................................................................................................... 9
3.4.1 triggering configuration download with sysfs ...................................................................................... 10
3.4.2 Automatically downloading the configuration on driver probe ............................................................ 10
3.5 Firmware Upgrade .......................................................................................................................................... 10
4.0 Debugging the Driver ................................................................................................................................................ 12
4.1 Enabling Driver Debug Messages – dev_dbg ................................................................................................ 12
4.2 Viewing Touch Events – evtest ....................................................................................................................... 12
4.3 Viewing Touch Events – Android getevent ..................................................................................................... 13
4.4 Debug File System Interface – sysfs .............................................................................................................. 14
4.4.1 mem_access ...................................................................................................................................... 15
4.4.2 debug_enable ..................................................................................................................................... 15
4.5 Improved Debug Interface .............................................................................................................................. 15
4.6 The mxt-app Utility .......................................................................................................................................... 15
Appendix A. Revision History .............................................................................................................................................. 18
1.0 INTRODUCTION
This application note introduces the maXTouch Linux driver, its features and available debug options to help developers
with driver integration. It also provides details on how to configure and build the kernel on a test platform.
The maXTouch Linux driver is designed to support the Linux input subsystem. This driver resides in the drivers/input/
touchscreen directory of the kernel and interfaces with the hardware to generate 2D touch events to the Linux input
subsystem.
The Linux driver can be compiled as an in-built driver or as a module to be loaded after the initial kernel boot. The
application note provides details regarding function of the driver and the debug options that are available through the
touch driver along with information regarding the testing of the touch driver.
This application note assumes that the user has a Linux based PC (either actual or a virtual machine) and has basic
knowledge of the Linux OS. It also assumes basic use of Github. All testing has been done using the Ubuntu OS version
16.04. Any critical libraries or tools that need to be installed will be mentioned in this application note.
The details within this document will mainly reference the standard Linux kernel. Where possible, differences between
the Linux “distributions” (for example, Ubuntu, Android) in terms of tools, directory locations or behavior will be noted.
AN3084
Using the maXTouch Linux Driver


Produktspecifikationer

Varumärke: Microchip
Kategori: Inte kategoriserad
Modell: ATMXT448UD

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