ConnectCore 6UL SBC Pro: How to get the MCA-RTC working and keeping the time actual with coin cell connected

Question

Hello,

I have a ConnectCore 6UL SBC Pro board with a new coin cell Varta CR1225 is connected to JP2 , V=3.3V.

The sysinfo output is:

||*Component*||*Version*
|| DUT | SN-020960, ccimx6ulsbc 0x02 SBCv4 board_ID=135.
|| U-Boot | U-Boot dub-2015.04-r9.2 (Jul 19 2017 - 17:11:30)
|| Firmware | dey-2.4-r1-20180915210659
|| Kernel | Linux btc 4.9.81-dey+g2c6ae4c #1 SMP PREEMPT Thu Aug 2 19:25:08 UTC 2018 armv7l GNU/Linux
|| meta-digi | HEAD:29add13409e8a0d8cc7f49276b060ae124b7bbe4
|| MCA | HW_VERSION=1 FW_VERSION=1.12
|| I/O Expander | HW_VERSION=1 FW_VERSION=0.02


The board is booted with network and the correct time is written to the RTC with
root@btc:~# hwclock -r
Tue Aug 6 15:59:41 2019 0.000000 seconds
I can read the hwclock:
root@btc:~# hwclock -r
Tue Aug 6 16:00:09 2019 0.000000 second

When I switch on the board 10 minutes or more later without any network connected it has the wrong time.

I also removed the /etc/timestamp in /etc/init.d/bootmisc.sh so that during boot the time read from the MCA-RTC is not read from the /etc/timestamp file.

It seems that the MCA RTC is working, I used the rtc_test:
root@btc:~# ./rtc_test -a
rtc_test 3.1 Copyright Digi International Inc.

RTC test/demo application

Current RTC date/time is 5-8-2019, 16:34:15.

Test results:

---

ioctl cmd RTC_RD_TIME: OK

Test finished

The MCA firmware was updated before to V.1.12 from file
mca_cc6ul.bin 27.756 07.05.2019 08:47

What else can I do to get a RTC working because keeping the correct time also without any network connection is essential for our application.

Best regards Uwe

Comments

Today I checked it with the 2.6 qt images: The RTC also didn't work.

These are the details:
Downloaded qt Images from ftp://ftp1.digi.com/support/digiembeddedyocto/2.6/r1/images/ccimx6ulsbc/fb/
ftp://ftp1.digi.com/support/digiembeddedyocto/2.6/r1/images/ccimx6ulsbc/fb/dey-image-qt-fb-ccimx6ulsbc.boot.ubifs
ftp://ftp1.digi.com/support/digiembeddedyocto/2.6/r1/images/ccimx6ulsbc/fb/dey-image-qt-fb-ccimx6ulsbc.rootfs.ubifs
to
dey-image-qt-fb-ccimx6ulsbc.boot.ubifs
dey-image-qt-fb-ccimx6ulsbc.rootfs.ubifs

Installed both files in Uboot, then booted:
Digi Embedded Yocto 2.6-r1 ccimx6ulsbc /dev/ttymxc4

ccimx6ulsbc login: root


BusyBox v1.29.3 (2019-04-16 23:41:21 UTC) built-in shell (ash)
Enter 'help' for a list of built-in commands.

root@ccimx6ulsbc:~# date
Mon Aug 12 08:01:08 UTC 2019
root@ccimx6ulsbc:~# hwclock -r
Wed Apr 17 00:41:25 2019  0.000000 seconds
root@ccimx6ulsbc:~# hwclock -w
root@ccimx6ulsbc:~# hwclock -r
Wed Apr 17 00:40:37 2019  0.000000 seconds
root@ccimx6ulsbc:~# date
Mon Aug 12 08:40:39 UTC 2019
root@ccimx6ulsbc:~# hwclock -r
Mon Aug 12 08:40:49 2019  0.000000 seconds
root@ccimx6ulsbc:~# uname -a
Linux root
ccimx6ulsbc 4.14.111-dey+g59580bb #1 PREEMPT Tue Apr 16 23:00:48 UTC 2019 armv7l GNU/Linux
root@ccimx6ulsbc:~# sysinfo
-------------------------------------
-                                   -
-         ENVIRONMENT TABLE         -
-                                   -
-------------------------------------

||*Component*||*Version*
|| DUT | SN-032162, digi,ccimx6ulsbc 0x02 SBCv4 board_ID=135.
|| U-Boot | U-Boot dub-2015.04-r9.2 (Jul 19 2017 - 17:11:30)
|| Firmware | dey-2.6-r1-20190416223249
|| Kernel | Linux ccimx6ulsbc 4.14.111-dey+g59580bb #1 PREEMPT Tue Apr 16 23:00:48 UTC 2019 armv7l GNU/Linux
|| meta-digi | HEAD:0078da95cb52f67e13c00131200299fd64a01d4b
|| MCA | HW_VERSION=1  FW_VERSION=1.12
|| I/O Expander | HW_VERSION=1  FW_VERSION=0.02

A new coin cell: V=3.17V
Switch off at appr. 10:41, unplug network cable
V drops to 2.74V

Restart at 12:13 after 92 minutes:
Digi Embedded Yocto 2.6-r1 ccimx6ulsbc /dev/ttymxc4

ccimx6ulsbc login: root


BusyBox v1.29.3 (2019-04-16 23:41:21 UTC) built-in shell (ash)
Enter 'help' for a list of built-in commands.

root@ccimx6ulsbc:~#
root@ccimx6ulsbc:~#
root@ccimx6ulsbc:~#
root@ccimx6ulsbc:~# date
Mon Aug 12 08:42:00 UTC 2019
root@ccimx6ulsbc:~# hwclock -r
Mon Aug 12 08:42:15 2019  0.000000 seconds

---

Further questions:
1. What type of coin cell did Digi use when they verified the RTC function?
2. What werer the voltages on JP with the coin cell connected when power on and also when power off?
3. How long did the coin cell kept the voltage?

Answer 1

Can you try it on the latest DEY-2.6 stock images?
Did you check the voltage on J2 after 10 min? does it drop?
What revision of cc6ul SBC Pro do you have?

Comments

Also with the newest image and RTC firmware it doesn't work.
These are the details:
Board serial number I182104032162, Board Vers. 4; Board ID 135
Images from  /support/digiembeddedyocto/2.6/r1/images/ccimx6ulsbc/fb/ date April 4th 2019:
dey-image-aws-ccimx6ulsbc.boot.ubifs    7.745.536
dey-image-aws-ccimx6ulsbc.rootfs.ubifs    89.645.056

First try: It didnt work, then update MCA firmware to
Version: v1.12
MD5SUMs:
mca_cc6ul.bin: d852924e23d628db36136a4b5d234f2e

root@ccimx6ulsbc:~# mca_fw_updater -f /var/volatile/mca_cc6ul.bin
The update process may take 20 seconds or more - DO NOT POWER OFF OR RESET

After reboot:
root@ccimx6ulsbc:~# date
Sat Aug 10 05:26:12 UTC 2019
root@ccimx6ulsbc:~# hwclock -w
root@ccimx6ulsbc:~# hwclock -r
Sat Aug 10 05:26:26 2019  0.000000 seconds
I take as new coin cell, V at coin cell is 3.25V

Switch off
V drops to 2.72V

Switch on without network at 7:49
V at coin cell meanwhile dropped to 2.74 if power on at the board
root@ccimx6ulsbc:~# hwclock -r
Sat Aug 10 05:27:44 2019  0.000000 seconds
root@ccimx6ulsbc:~# date
Sat Aug 10 05:29:05 UTC 2019

Time is wrong.