Wexler TAB A720

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Wexler TAB A720
Wexler TAB A720-1.jpg
Manufacturer Wexler (dead link)
Dimensions 194mm x 114mm x 9mm
Release Date November 2014
Website Device Product Page
Specifications
SoC A23 @ 1.5Ghz
DRAM 512MiB DDR3 @ 240MHz
NAND 4GB
Power USB, 2500mAh 3.7V Li-Ion battery
Features
LCD 800x480 (7" 16:9)
Touchscreen X-finger capacitive/resistive (Silead GSL1680)
Video LCD
Audio 3.5mm headphone plug, internal speaker, internal microphone
Network WiFi 802.11 b/g/n (Espressif ESP8089)
Storage µSD
USB 1 USB2.0 OTG
Camera 0.3MP (640x480) front

Identification

On the back of the device, the following is printed:

WEXLER.TAB A720

The PCB has the following silkscreened on it:

A23_M7085_L_V02
2014_C5_29

In android, under Settings->About Tablet, you will find:

  • Model Number: TAB A720
  • Build Number: TAB A720_20141115_3.2.0_INT

Sunxi support

Current status

Unsupported in mainline kernel, mostly because of non-standard LCD (but really i don't know).
Patches for kernel and U-Boot can be found in this repository: https://gitlab.com/astroncia/sunxi-wexler-tab-a720

Tested and working with patches:

Display
U-Boot v2021.07
Kernel 5.14.0 (commit 78e709522d2c012cb0daad2e668506637bffb7c2)
DTB
SDcard
USB OTG
Brightness
Hardware keys
Mali / lima (GPU)
Audio (by default speaker is off, enable it by uncommenting in device tree)
Touchscreen (use this firmware https://gitlab.com/astroncia/sunxi-wexler-tab-a720/-/blob/master/firmware/gsl1680-wexler-taba720.fw)
(my xorg.conf.d (calibration) for touchscreen is here: https://gitlab.com/astroncia/sunxi-wexler-tab-a720/-/tree/master/touchscreen_config/xorg.conf.d)

Working but with problems:

Wifi - use this kernel module https://github.com/Icenowy/esp8089/tree/cleanup (Known problem - cannot connect to hidden SSID, not tested with normal)

Not working:

Cedrus (hardware media acceleration)
Rotation
Accelerometer (it's mxc622x, no known driver for mainline)
Camera

Problems encountered:

  1. Kernel 5.14.0 does not shutdown fully (screen is off but power is on) (on 5.8.0 all OK)
Android modules
gslX680new 134112 0 - Live 0x00000000 (F)
mxc622x 4025 0 - Live 0x00000000
rtl8150 8115 0 - Live 0x00000000
mcs7830 4948 0 - Live 0x00000000
qf9700 5188 0 - Live 0x00000000
asix 12322 0 - Live 0x00000000
sunxi_keyboard 2749 0 - Live 0x00000000
sw_device 12200 0 - Live 0x00000000
vfe_v4l2 217660 0 - Live 0x00000000
gc0308 9360 1 - Live 0x00000000
vfe_subdev 3827 2 vfe_v4l2,gc0308, Live 0x00000000
vfe_os 3175 2 vfe_v4l2,vfe_subdev, Live 0x00000000
cci 2954 1 gc0308, Live 0x00000000
videobuf_dma_contig 3821 1 vfe_v4l2, Live 0x00000000
videobuf_core 15500 2 vfe_v4l2,videobuf_dma_contig, Live 0x00000000
leds_sunxi 1279 0 - Live 0x00000000
mali 179969 15 - Live 0x00000000 (O)
lcd 7184 0 - Live 0x00000000
disp 1045213 8 mali,lcd, Live 0x00000000
nand 256473 8 - Live 0x00000000 (O)

Manual build

You can build things for yourself by following our Manual build howto and by choosing from the configurations available below.

U-Boot

Mainline U-Boot

For unknown reason, git u-boot is not working with tablet, use v2021.07 release
First, apply this patch: https://gitlab.com/astroncia/sunxi-wexler-tab-a720/-/blob/master/patches/U-BOOT_0001-Add-Wexler-TAB-A720-support.patch
Then, use the Wexler_TAB_A720_defconfig build target.

Linux Kernel

Mainline kernel

First, apply this patch: https://gitlab.com/astroncia/sunxi-wexler-tab-a720/-/blob/master/patches/LINUX_0001-Add-Wexler-TAB-A720-support.patch
Then, use the sun8i-a23-wexler-tab-a720.dtb device-tree binary.

FEL mode

With SD card: https://linux-sunxi.org/FEL#Through_a_special_SD_card_image
I do not tried search FEL buttons.

Adding a serial port (voids warranty)

DEVICE UART pads

This section explains how to attach a serial port to the device. Make sure it refers to our UART howto. For a development board, you can just mention how to find the header with the pins and include a picture, and you can remove the warranty voiding warning.

Device disassembly

See the Q8 tablet format disassembly page.

Locating the UART

Describe how to find the RX,TX,GND signals here, and mention the UART howto.

Pictures