Uart pinout on Ixora V1.1

Technical Support
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1

Hi all,

I followed this link for flashing Buildroot file(s) into the Apalis iMX6 board : Flashing Buildroot image files on Apalis iMX6 - Technical Support - Toradex Community

My problem is I could not connect to the uart 1 so interact with the console. My initial setup was as in the following image :

[upload|tEhTHyyHMd9V7zz3aMQ9qxx5diI=]

with the thinking of following pinout scheme:

2-4-6-8-10
1-3-5-7-9

But no message crashed out.

Then I thought about another setup with following pinout scheme:
6-7-8-9-10
1-2-3-4-5

[upload|PwLkYbPQc/ap7lPaTdfP+/f2aXc=]

And surprisingly I could see the bootup message crashed out from the Apalis iMX6. But still I could not input any character to the board.

Could anybody confirm me about the correct pinout scheme of UART1 on Ixora board, please?

Cables’ color codes :
Yellow : PC-TxD
White : PC-RxD
Gray : GND

Many thanks and best regards,
Khang

2

A regular insulation displacement connector aka IDC’s pinout is indeed as follows:

2-4-6-8-10
1-3-5-7-9

Please note that on our Ixora datasheet page 28 by UART1_RS232_TXD resp. UART1_RS232_RXD we mean from the module’s side so you are looking at connecting your cables as follows:

3: UART1_RS232_RXD: Yellow : PC-TxD
5: UART1_RS232_TXD: White : PC-RxD
9: GND: Gray : GND

3

Thanks marcel.tx for confirmation and that was what I did initially but the board just crashed something like Japanese words as following :

Welcome to minicom 2.7.1

OPTIONS: I18n                                                                
Compiled on Aug 13 2017, 15:25:34.                                           
Port /dev/ttyUSB0, 16:17:43                                                  
                                                                             
Press CTRL-A Z for help on special keys                                      
�!�!������=!;!!���������￟��}='-�-eO忓���i�ky��J��=%%57��ڔ��-�忿��ue�ݽ�-�忟��sYgAYwoy�����sYgAYwoy���U-#1�753='뿿5#-#%5##�/5'���}='-�����-eO�����K.7.1ww[��-%-#1�����-Պ#�9!%%=#7��i�kl+����y��彯U�ۅ!�������������13�7;��59;���k'�����������������������o勿

And curiously that the “irregular” setup was the only one with which I could see the readable output from the board but without being able to interact with it (i.e. to hit any key to interrupt the boot) since its RxD signal was not correctly wired :

Welcome to minicom 2.7.1

OPTIONS: I18n                                                                
Compiled on Aug 13 2017, 15:25:34.                                           
Port /dev/ttyUSB0, 16:18:58                                                  
                                                                             
Press CTRL-A Z for help on special keys                                      
                                                                             
�                                                                            
 Industrial temperature grade DDR3 timings.                                  
Trying to boot from MMC1                                                     
                                                                             
                                                                             
U-Boot 2016.11-1.7.0+gf4db39ecb6 (Jul 30 2018 - 16:50:57 +0200)
                                        
CPU:   Freescale i.MX6Q rev1.5 at 792 MHz
Reset cause: POR                        
I2C:   ready                            
DRAM:  2 GiB                            
PMIC:  device id: 0x10, revision id: 0x21, programmed
MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
Using default environment

In:    serial_mxc
Out:   serial_mxc
Err:   serial_mxc
Model: Toradex Apalis iMX6 Quad 2GB IT V1.1C, Serial# 10486824
Net:   using PHY at 7
FEC [PRIME]
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc1 is current device
Scanning mmc 1:1...
MMC: no card present
switch to partitions #0, OK
mmc0(part 0) is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
reading /boot.scr
583 bytes read in 11 ms (51.8 KiB/s)
## Executing script at 17000000
reading /tezi.itb
21054164 bytes read in 591 ms (34 MiB/s)
## Loading kernel from FIT Image at 12200000 ...
   Using 'config@1' configuration
   Trying 'kernel@1' kernel subimage
     Description:  Linux Kernel 4.1
     Type:         Kernel Image
     Compression:  uncompressed
     Data Start:   0x122000dc
     Data Size:    5343320 Bytes = 5.1 MiB
     Architecture: ARM
     OS:           Linux
     Load Address: 0x11000000
     Entry Point:  0x11000000
     Hash algo:    md5
     Hash value:   4194601560c21ef73d9a9f415fbf0f53
   Verifying Hash Integrity ... md5+ OK
## Loading ramdisk from FIT Image at 12200000 ...
   Using 'config@1' configuration
   Trying 'ramdisk@1' ramdisk subimage
     Description:  SquashFS RAMdisk
     Type:         RAMDisk Image
     Compression:  uncompressed
     Data Start:   0x12718a1c
     Data Size:    15659008 Bytes = 14.9 MiB
     Architecture: ARM
     OS:           Linux
     Load Address: unavailable
     Entry Point:  unavailable
     Hash algo:    md5
     Hash value:   55f3d30f4f689acf470ada9d0cf4b360
   Verifying Hash Integrity ... md5+ OK
## Loading fdt from FIT Image at 12200000 ...
   Using 'config@1' configuration
   Trying 'fdt@1' fdt subimage
     Description:  Apalis iMX6 Device Tree
     Type:         Flat Device Tree
     Compression:  uncompressed
     Data Start:   0x13607ae4
     Data Size:    50361 Bytes = 49.2 KiB
     Architecture: ARM
     Hash algo:    md5
     Hash value:   67b35a20ece1bd6c1c0639fed8dc7b47
   Verifying Hash Integrity ... md5+ OK
   Booting using the fdt blob at 0x13607ae4
   Loading Kernel Image ... OK
   Loading Device Tree to 2fff0000, end 2ffff4b8 ... OK

Starting kernel ...

[    0.912718] snvs-secvio 20cc000.caam-snvs: can't get snvs clock
[    1.435604] imx6q-pcie 1ffc000.pcie: phy link never came up
[    1.441229] imx6q-pcie 1ffc000.pcie: failed to initialize host
[    1.451689] rtc-ds1307 1-0068: hctosys: unable to read the hardware clock
Running /etc/rc.local...
Apalis-iMX6_ToradexEasyInstaller_1.7-20180731

Welcome to Toradex Easy Installer

This is a Linux based installer for Toradex modules. Currently the
installer does not have a serial console interface. You can use the
Toradex Easy Installer through any of the available display interfaces
using USB mouse/keyboard or via network using VNC. Use:
  # ip addr show eth0
to display the Ethernet IP address or use USB RNDIS at IP 192.168.11.1.

I think maybe there’s some HW problem with the Apalis iMX6 module !?!?

BR,
Khang

4

Hi Khang

The signals on X22 went through a RS232 transceiver and are not CMOS level UART signals.

Your cabling looks like you might use a CMOS level converter to USB which might explain the strange behavior. So what do you use between the Ixora X22 and your PC’s connector?

Max

5

Hi Max,

I use the following CP2102 USB to UART Bridge Controller :

1496-img-1250-opt.jpg

It works well with my Raspberry Pi, is it the cause of this problem ?

BR,
Khang

6

Hi

Yes, that is the cause of the problem.

You would need an adapter RS232 levels, not CMOS/TTL levels.

E.g. some adapter cable to get a DB9 connector. Then you would need an adapter from RS232 to USB. Refer to step 2 and 3 here.

Max

7

Thanks Max for pointing out the problem of RS232 - UART adapter. I tested on the DB9 connector and it works well as documented.

BR,
Khang