X728 Pi4 RTC not working

• X728
• rtc
• pi4
• ubuntu

• R-

  Robert -

  12/18/20, 11:02 PM
  I purchased the X728 ups hat to be used with a Pi 4.

  I am having issues with RTC.

  I'm running Ubuntu Server 20.04.

   

  To rule out issues as my fault, here is what I did:

   - in /boot/firmware/usercfg.txt i have added:

   - dtparam=i2c_arm=on

   - dtoverlay=i2c-rtc,ds1307

   

  ls -l /dev/i2c*
  crw-rw---- 1 root i2c 89, 1 Apr  1  2020 /dev/i2c-1

   

  ls -la /dev/rt*
  lrwxrwxrwx 1 root root      4 Apr  1  2020 /dev/rtc -> rtc0
  crw------- 1 root root 248, 0 Apr  1  2020 /dev/rtc0

   

  sudo i2cdetect -y 1
       0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
  00:          -- -- -- -- -- -- -- -- -- -- -- -- --
  10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
  20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
  30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
  40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
  50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
  60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
  70: -- -- -- -- -- -- -- --  

   

  sudo hwclock -v
  hwclock from util-linux 2.34
  System Time: 1608303236.603336
  Trying to open: /dev/rtc0
  Using the rtc interface to the clock.
  Assuming hardware clock is kept in UTC time.
  Waiting for clock tick...
  ioctl(4, RTC_UIE_ON, 0): Invalid argument
  Waiting in loop for time from /dev/rtc0 to change
  hwclock: ioctl(RTC_RD_TIME) to /dev/rtc0 to read the time failed: Connection timed out
  ...synchronization failed

   

  sudo dmesg | grep -i rtc
  [    0.000000] Kernel command line:  coherent_pool=1M 8250.nr_uarts=1 snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 snd_bcm2835.enable_headphones=1 bcm2708_fb.fbwidth=1824 bcm2708_fb.fbheight=984 bcm2708_fb.fbswap=1 smsc95xx.macaddr=DC:A6:32:A4:B5:B5 vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000  net.ifnames=0 dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=LABEL=writable rootfstype=ext4 elevator=deadline rootwait fixrtc quiet splash
  [    1.861664] hctosys: unable to open rtc device (rtc0)
  [    2.460567] rtc-ds1307 1-0068: registered as rtc0
  [   25.962250] rtc-ds1307 1-0068: read error -110
  [   26.986155] rtc-ds1307 1-0068: read error -110
  [   35.562185] rtc-ds1307 1-0068: read error -110
  [   36.586157] rtc-ds1307 1-0068: read error -110
  [   37.610264] rtc-ds1307 1-0068: read error -110
  [   52.138424] rtc-ds1307 1-0068: write error -110
  [   53.162442] rtc-ds1307 1-0068: read error -110

   

   

  The TTY is also getting flooded with:

   i2c-bcm2835 : i2c transfer timed out

  rtc-ds1307 1-0068: write error -110

   

   

  Is this a bad board?

  Please advise.

   
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• R-

  Robert -

  12/19/20, 12:09 AM

  Tested on Raspberry OS lite. Seems to work.

   

  sudo hwclock -v

  hwclock from util-linux 2.33.1

  System Time: 1608307733.168204

  Trying to open: /dev/rtc0

  Using the rtc interface to the clock.

  Last drift adjustment done at 1608307717 seconds after 1969

  Last calibration done at 1608307717 seconds after 1969

  Hardware clock is on UTC time

  Assuming hardware clock is kept in UTC time.

  Waiting for clock tick...

  ioctl(4, RTC_UIE_ON, 0): Invalid argument

  Waiting in loop for time from /dev/rtc0 to change

  ...got clock tick

  Time read from Hardware Clock: 2020/12/18 16:08:54

  Hw clock time : 2020/12/18 16:08:54 = 1608307734 seconds since 1969

  Time since last adjustment is 17 seconds

  Calculated Hardware Clock drift is 0.000000 seconds

  2020-12-18 16:08:53.160769+00:00

   

  But why doesn't it work with Ubuntu?

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• R-

  Robert -

  12/19/20, 12:45 AM

  Apparenly on a freshly installed Ubuntu it works.

  Interesting...

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