iMX6 Rex Basic Accessing and Testing Peripherals

Elemental operations of iMX6 Rex Development Kit interfaces in Basic configuration are shown on this page.

Prerequisites

Hardware

DC power supply (12V, 1A)
iMX6 Rex Module Basic
iMX6 Rex Base Board

Peripherals and Accessories

1x FullHD monitor with Audio output
1x MicroSD card
2x USB FLASH drive

Cables

Ethernet cable
HDMI cable
Micro USB cable
RS-232 cable

User button

Input: Press and hold USER button (pca9535 driver is used)
Output: GPIO register is read and displayed state of the button

root@imx6-rexbasic:~# echo 511 > /sys/class/gpio/export
root@imx6-rexbasic:~# echo in > /sys/class/gpio/gpio511/direction
root@imx6-rexbasic:~# cat /sys/class/gpio/gpio511/value
1
root@imx6-rexbasic:~# cat /sys/class/gpio/gpio511/value
0

Reset button

Input: Press the RESET button
Output: Module will execute bootloader immediately with "Reset cause: POR"
Note: Module should never freeze or hang after the reset button was pressed. Testing the operation 10 times gives a reliable result

U-Boot 2014.10-dirty (Mar 12 2016 - 11:34:54)

CPU:   Freescale i.MX6Q rev1.2 at 792 MHz
Reset cause: POR
Board: MX6 Rex - basic
I2C:   ready
DRAM:  2 GiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
SF: Detected SST25VF032B with page size 256 Bytes, erase size 4 KiB, total 4 MiB
*** Warning - bad CRC, using default environment

In:    serial
Out:   serial
Err:   serial
Net:   FEC [PRIME]
Hit any key to stop autoboot:  0

Ethernet

Input: None
Output: Device driver is available
Note: MAC address should be identical with the address on the sticker placed on module

root@imx6-rexbasic:~# ip addr show dev eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0d:15:00:cc:e2 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::20d:15ff:fe00:cce2/64 scope link

Input: Plug Ethernet cable into connector and issue DHCP command
Output: IPv4 address is assigned

root@imx6-rexbasic:~# dmesg | tail
...
libphy: 2188000.ethernet:03 - Link is Up - 100/Full
IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready

root@imx6-rexbasic:~# udhcpc -i eth0
udhcpc (v1.22.1) started
Sending discover...
Sending select for 192.168.0.178...
Lease of 192.168.0.178 obtained, lease time 600

HDMI Output

Input: Connect LCD monitor to base board
Output: Desktop UI is displayed correctly

I2C

Input: Scan I2C bus 1
Output: Available devices:

GPIO expander (0x27)
touchscreen TSC2007 (0x48)
HDMI Output EDID (0x50)
RTC clock (0x51)
EEPROM (0x57)

Note: HDMI monitor must be disconnected otherwise I2C bus 1 scanning bus might freeze.

root@imx6-rexbasic:~# i2cdetect -y 1 
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- 18 -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- UU -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- -- 
50: UU UU -- -- -- -- -- UU -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --

Input: Trigger I2C GPIO expander detection.
Output: GPIO expander is detected

root@imx6-rexbasic:~# echo -n "1-0027" > /sys/bus/i2c/drivers/pca953x/unbind
root@imx6-rexbasic:~# echo -n "1-0027" > /sys/bus/i2c/drivers/pca953x/bind
pca953x 1-0027: interrupt support not compiled in

Input: Trigger I2C RTC detection
Output: RTC is detected

root@imx6-rexbasic:~# echo -n "1-0051" > /sys/bus/i2c/drivers/rtc-pcf8563/unbind
root@imx6-rexbasic:~# echo -n "1-0051" > /sys/bus/i2c/drivers/rtc-pcf8563/bind
rtc-pcf8563 1-0051: chip found, driver version 0.4.3
rtc-pcf8563 1-0051: low voltage detected, date/time is not reliable.
rtc-pcf8563 1-0051: low voltage detected, date/time is not reliable.
rtc rtc1: invalid alarm value: 2030-10-20 41:58:0
rtc-pcf8563 1-0051: rtc core: registered rtc-pcf8563 as rtc1

Input: Trigger I2C EEPROM detection
Output: I2C EEPROM is detected

root@imx6-rexbasic:~# echo -n "1-0057" > /sys/bus/i2c/drivers/at24/unbind
root@imx6-rexbasic:~# echo -n "1-0057" > /sys/bus/i2c/drivers/at24/bind 
at24 1-0057: 256 byte 24c02 EEPROM, writable, 1 bytes/write

Input: Write and read data from I2C EEPROM
Output: If successful, console text 'Data are the same' should appear

root@imx6-rexbasic:~# echo -n "0123" > eeprom_in
root@imx6-rexbasic:~# cat eeprom_in > /sys/bus/i2c/devices/1-0057/eeprom
root@imx6-rexbasic:~# head -c 4 /sys/bus/i2c/devices/1-0057/eeprom > eeprom_out
root@imx6-rexbasic:~# diff eeprom_in eeprom_out && echo "Data are the same"
Data are the same

Alternative test

Input: List I2C bus 1
Output: Available devices are displayed

root@imx6-rexbasic:~# ls /sys/bus/i2c/devices/i2c-1 | grep ^[1]
1-0048
1-0050

User LED

Input: None
Output: Red LED assembled on module switches from ON to OFF state with heartbeat pulses afterwards

root@imx6-rexbasic:~# echo -n "none" > /sys/devices/soc0/leds*/leds/module-led/trigger 
root@imx6-rexbasic:~# echo -n "1" > /sys/devices/soc0/leds*/leds/module-led/brightness
root@imx6-rexbasic:~# echo -n "0" > /sys/devices/soc0/leds*/leds/module-led/brightness
root@imx6-rexbasic:~# echo -n "heartbeat" >  /sys/devices/soc0/leds*/leds/module-led/trigger

Input: GPIO expander PCA9535 driver
Output: Red LED assembled on the base board switches from ON to OFF state

root@imx6-rexbasic:~# echo 510 > /sys/class/gpio/export
root@imx6-rexbasic:~# echo out > /sys/class/gpio/gpio510/direction
root@imx6-rexbasic:~# echo 1 > /sys/class/gpio/gpio510/value
root@imx6-rexbasic:~# echo 0 > /sys/class/gpio/gpio510/value

DDR memory

Input: None
Output: Memory test passes without any errors

root@imx6-rexbasic:~# memtester 2G 1   
memtester version 4.1.3 (32-bit)
Copyright (C) 2010 Charles Cazabon.
Licensed under the GNU General Public License version 2 (only).

pagesize is 4096
pagesizemask is 0xfffff000
want 2048MB (2147483648 bytes)
got  267MB (280412160 bytes), trying mlock ...locked.
Loop 1/1:
  Stuck Address       : ok         
  Random Value        : ok
  Compare XOR         : ok
  Compare SUB         : ok
  Compare MUL         : ok
  Compare DIV         : ok
  Compare OR          : ok
  Compare AND         : ok
  Sequential Increment: ok
  Solid Bits          : ok         
  Block Sequential    : ok         
  Checkerboard        : ok         
  Bit Spread          : ok         
  Bit Flip            : ok         
  Walking Ones        : ok         
  Walking Zeroes      : ok         

Done.

Further information about DDR3 memories and its calibration can be accessed in Memory Calibration details.

SD card

Bottom slot SD card (mmcblk2)

Input: Plug SD card with a filesystem and boot-up the module
Output: Module boots up successfully

root@imx6-rexbasic:~# dmesg | grep -i "Kernel command line"
Kernel command line: console=ttymxc0,115200 root=/dev/mmcblk2p2 rootwait rw

SPI Flash Memory

Input: Trigger M25P80 flash detection
Output: SPI Flash sst25vf016b(sst25vf032b) is detected

root@imx6-rexbasic:~# echo -n "spi2.0" > /sys/bus/spi/drivers/m25p80/unbind
root@imx6-rexbasic:~# echo -n "spi2.0" > /sys/bus/spi/drivers/m25p80/bind 
m25p80 spi2.0: found sst25vf032b, expected m25p32
m25p80 spi2.0: sst25vf032b (4096 Kbytes)

Input: Write and read data from M25P80 flash
Output: If successful, console text 'Data are the same' should appear

root@imx6-rexbasic:~# echo -n "0123" > mtd_in
root@imx6-rexbasic:~# mtd_debug write /dev/mtd0 0 4 mtd_in 
Copied 4 bytes from mtd_in to address 0x00000000 in flash
root@imx6-rexbasic:~# mtd_debug read /dev/mtd0 0 4 mtd_out
Copied 4 bytes from address 0x00000000 in flash to mtd_out
root@imx6-rexbasic:~# diff mtd_in mtd_out && echo "Data are the same"
Data are the same

UART serial console

Input: Connect RS-232 cable into the base board connector and open serial console with baud rate 115200 8n1
Output: The board is controlled and responsive to serial terminal commands

root@imx6-rexbasic:~# uname -a
Linux imx6-rexbasic 3.14.58-yocto+g11e5ba3 #1 SMP PREEMPT Sun Mar 13 20:20:31 CET 2016 armv7l GNU/Linux

USB

Input: Plug USB flash drive with single VFAT partition into the bottom USB connector
Output: Filesystem recognises the flash drive and automatically mounts it. SMC Hub with ID 0424:2514 is mounted

root@imx6-rexbasic:~# lsusb
Bus 001 Device 003: ID 1bc7:0021 Telit HE910
Bus 001 Device 005: ID 054c:0243 Sony Corp. MicroVault Flash Drive
Bus 001 Device 004: ID 0930:6544 Toshiba Corp. Kingston DataTraveler 2.0 Stick (2GB)
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

root@imx6-rexbasic:~# mount | grep /run/media/sd*
/dev/sda1 on /run/media/sda1 type vfat (rw,relatime,gid=6,fmask=0007,dmask=0007,allow_utime=0020,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)

Input: Generate a dummy file and copy it into USB flash drive
Output: Generated file and copied file have the same checksum

root@imx6-rexbasic:~# rm -f file.txt /run/media/sda1/file.txt 
root@imx6-rexbasic:~# dd if=/dev/urandom of=file.txt count=1024 bs=1024
1024+0 records in
1024+0 records out
1048576 bytes (1.0 MB) copied, 0.435456 s, 2.4 MB/s
root@imx6-rexbasic:~# cp file.txt /run/media/sda1/
root@imx6-rexbasic:~# md5sum file.txt /run/media/sda1/file.txt
33ef96efccbbf570bfce477735ed2068  file.txt
33ef96efccbbf570bfce477735ed2068  /run/media/sda1/file.txt
root@imx6-rexbasic:~# rm file.txt /run/media/sda1/file.txt

USB OTG

Input: Load USB serial gadget driver and connect base board to host PC over micro USB cable
Output: Driver is successfully loaded and host PC detects a new USB serial gadget device

iMX6 Rex Development Kit:

root@imx6-rexbasic:~# modprobe -i g_serial
g_serial gadget: Gadget Serial v2.4
g_serial gadget: g_serial ready
root@imx6-rexbasic:~# g_serial gadget: high-speed config #2: CDC ACM config

Host PC:

user@voipac:~$ lsusb 
...
Bus 001 Device 014: ID 0525:a4a7 Netchip Technology, Inc. Linux-USB Serial Gadget (CDC ACM mode)
...

Touchscreen

Input: Search kernel log for TSC2007 chip
Output: TSC2007 chip is detected and bound as an input device

root@imx6-rexbasic:~# dmesg | grep -i tsc2007
input: TSC2007 Touchscreen as /devices/soc0/soc.0/2100000.aips-bus/21a4000.i2c/i2c-1/1-0048/input/input0
evbug: Connected device: input0 (TSC2007 Touchscreen at 1-0048/input0)

Input: Press the touchscreen
Output: Touchscreen events are generated

root@imx6-rexbasic:~# evtest /dev/input/by-path/platform-21a4000.i2c-event 
Input driver version is 1.0.1
Input device ID: bus 0x18 vendor 0x0 product 0x0 version 0x0
Input device name: "TSC2007 Touchscreen"
Supported events:
  Event type 0 (EV_SYN)
  Event type 1 (EV_KEY)
    Event code 330 (BTN_TOUCH)
  Event type 3 (EV_ABS)
    Event code 0 (ABS_X)
      Value   3529
      Min        0
      Max     4095
    Event code 1 (ABS_Y)
      Value    375
      Min        0
      Max     4095
    Event code 24 (ABS_PRESSURE)
      Value      0
      Min        0
      Max     4095
Properties:
Testing ... (interrupt to exit)
Event: time 1457899907.959665, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1
Event: time 1457899907.959665, type 3 (EV_ABS), code 0 (ABS_X), value 1657
Event: time 1457899907.959665, type 3 (EV_ABS), code 1 (ABS_Y), value 2486
Event: time 1457899907.959665, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 3268
Event: time 1457899907.959665, -------------- EV_SYN ------------
Event: time 1457899907.969094, type 1 (EV_KEY), code 330 (BTN_TOUCH), value 0
Event: time 1457899907.969094, type 3 (EV_ABS), code 24 (ABS_PRESSURE), value 0
Event: time 1457899907.969094, -------------- EV_SYN ------------

Alternative test

Input: Press the touchscreen
Output: Touchscreen events are generated

root@imx6-rexbasic:~# hexdump -C /dev/input/event0 
00000000  79 ca e5 56 cd a3 07 00  01 00 4a 01 01 00 00 00  |y..V......J.....|
00000010  79 ca e5 56 cd a3 07 00  03 00 00 00 2f 08 00 00  |y..V......../...|
00000020  79 ca e5 56 cd a3 07 00  03 00 01 00 a7 07 00 00  |y..V............|
00000030  79 ca e5 56 cd a3 07 00  03 00 18 00 64 06 00 00  |y..V........d...|
00000040  79 ca e5 56 cd a3 07 00  00 00 00 00 00 00 00 00  |y..V............|
00000050  79 ca e5 56 a7 c4 07 00  01 00 4a 01 00 00 00 00  |y..V......J.....|
00000060  79 ca e5 56 a7 c4 07 00  03 00 18 00 00 00 00 00  |y..V............|
00000070  79 ca e5 56 a7 c4 07 00  00 00 00 00 00 00 00 00  |y..V............|

iMX6 Rex Basic Accessing and Testing Peripherals

Contents

Prerequisites

Hardware

Peripherals and Accessories

Cables

User button

Reset button

Ethernet

HDMI Output

I2C

Alternative test

User LED

DDR memory

SD card

Bottom slot SD card (mmcblk2)

SPI Flash Memory

UART serial console

USB

USB OTG

Touchscreen

Alternative test

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