Microchip ATMXT448UD Handleiding


Lees hieronder de 📖 handleiding in het Nederlandse voor Microchip ATMXT448UD (20 pagina's) in de categorie Niet gecategoriseerd. Deze handleiding was nuttig voor 27 personen en werd door 2 gebruikers gemiddeld met 4.5 sterren beoordeeld

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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
AN3084
DS00003084A-page 2 2019 Microchip Technology Inc.
1.1 SAMA5D3 Xplained Board
The platform used for testing and integration is the SAMA5D3 Xplained board. This SOC is a Cortex A5 ARM MPU. The
pre-built demonstration Yocto project provides a basis for touch driver testing and integration.
In this application note, the demo project linux4sam-poky-sam5d3_xplained_pda-5. 7 will be used. This can be found
at the following link:
ftp://www. at91.com/pub/demo/linux4sam_5.7/linux4sam-poky-sama5d3_xplained_pda4-5.7.zip
This project should be extracted to a local directory on the user’s PC. The content will be updated and used on the
SAMA5D3 Xplained board to develop and test the touch driver. Note that only the compressed kernel image (zImage)
and device tree binaries (.dtb) will be updated for testing; the u-boot, at91bootstrap and the Yocto project layer files
will not be modified.
The following link contains additional information regarding the demo projects for the SAMA5D3 Xplained board and
other supporting tools for the board:
https://www.at91.com/linux4sam/bin/view/Linux4SAM/Sama5d3XplainedMainPage
FIGURE 1: SAMA5D3 XPLAINED BOARD
1.2 SAM Boot Assistance (SAM-BA)
The SAM Boot Assistance (SAM-BA) in-system programmer is Microchip’s software for programming Microchip ARM
Thumb-based MPUs. It is run on the Linux OS platform on the user’s PC to re-program the MPU on the SAMA5D3
Xplained board.
Follow the link below to download and extract the SAM-BA program to a directory.
https://github.com/atmelcorp/sam-ba/releases
NOTE At time of writing, the latest version of the demo project is version 6.0. However, a hardware or u-boot
change is required to enable video to work. See the following locations for more details:
https://www.at91.com/linux4sam/bin/view/Linux4SAM/U-Boot#PDA_detection_at_boot
or
https://www.at91.com/linux4sam/bin/view/Linux4SAM/SelectingPDAatBoot
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2019 Microchip Technology Inc. DS00003084A-page 3
1.3 Putty Terminal Program
To monitor activity during flashing and accessing the SAMA5D3 board, the Linux putty terminal application is used for
serial communication. The putty terminal program is used throughout this application note to communicate to the
driver and exercise the various features that are supported by the maXTouch devices.
The baud rate settings for serial communication are listed in Table 1.
To install putty enter the following commands in the terminal window.
sudo apt-get update
sudo apt install putty
A USB to TTL serial cable is required to connect from the USB port of the PC to the J23 DBGU port of the SAMA5D3
evaluation board.
To find the USB port that is used for the USB to TTL serial cable, identify the USB connection by monitoring the last
lines of the dmesg command when the cable is plugged into the local PC. This will provide the device name assigned
by the Linux operating system. For example, in the dmesg listing below, the device /dev/ttyUSB0 will be used to
configure the terminal emulator (as in the green text below).
[167305. 231492] usb 1-5: new full-speed USB device number 16 using xhci_hcd
[167305. 386051] usb 1-5: New USB device found, idVendor=0403, idProduct=6001
[167305. 386057] usb 1-5: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[167305. 386061] usb 1-5: Product: FT232R USB UART
[167305. 386065] usb 1-5: Manufacturer: FTDI
[167305. 386069] usb 1-5: SerialNumber: A505MLX6
[167306. 762669] usbcore: registered new interface driver usbserial_generic
[167306. 762696] usbserial: USB Serial support registered for generic
[167306. 768859] usbcore: registered new interface driver ftdi_sio
[167306. 768867] usbserial: USB Serial support registered for FTDI USB Serial Device
[167306. 768915] ftdi_sio 1-5:1. 0: FTDI USB Serial Device converter detected
[167306. 768946] usb 1-5: Detected FT232RL
[167306. 769108] usb 1-5: FTDI USB Serial Device converter now attached to ttyUSB0
TABLE 1: BAUD RATE SETTINGS
Parameter Setting
Baud rate 115200
Data 8 bits
Parity None
Stop 1 bit
Flow control None


Product specificaties

Merk: Microchip
Categorie: Niet gecategoriseerd
Model: ATMXT448UD

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