Difference between revisions of "RTC Cape"

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==Descriptions==
 
==Descriptions==
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[[File:RTCCape650.jpg|border|right|link=|300px|RTC Cape]]
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[[File:RTC-SlantedTop650.jpg|border|right|300px|RTC Cape]]
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The RTC Cape provides tracking capability for the BeagleBone Black even when the power is lost. This cape features the MCP79410 I2C-based real-time clock/calendar that can generate square waves at different frequencies or alarm interrupts.
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The RTC Cape provides time tracking capability for the BeagleBone Black even when the power is lost. This cape features the DS1338 I2C-based real-time clock/calendar and a holder for a coin battery type CR2032. Setup, reading, and setting up time is easy with the provided device tree overlay.
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==Revision Changes==
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===Revision A1===
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Initial release of RTC Cape.
  
  
  
  
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==Software Support & Compatibility==
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* All revisions are compatible with BeagleBone and BeagleBone Black using 3.8 kernel.
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<!--* Device tree files: [http://elinux.org/images/e/e3/BBB-RTC-01-00A1.tar.gz BBB-RTC-01-00A1.tar.gz]-->
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* Latest software for BeagleBone Black can be downloaded [http://elinux.org/Beagleboard:Updating_The_Software here].
  
  
  
  
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==Getting Started==
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The instructions below are performed on Debian release 2014-05-14 (Linux beaglebone 3.8.13-bone50 #1 SMP Tue May 13 13:24:52 UTC 2014 armv7l GNU/Linux).
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* Connect your BeagleBone Black to the internet, log in as root, download the device tree files and extract them to /lib/firmware of your BBB:
 +
<code>
 +
    cd /lib/firmware
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    wget https://github.com/CircuitCo/RTC-Cape/raw/docs/BBB-RTC-01-00A1.tar.gz
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    tar xvzf BBB-RTC-01-00A1.tar.gz
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</code>
  
  
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* Load the device tree overlay for your RTC Cape:
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<code>
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    echo BBB-RTC-01:00A1 > /sys/devices/bone_capemgr*/slots
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</code>
  
  
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* Check to ensure the overlay is loaded. In the messages below, the DS1338 is registered as rtc1:
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<code>
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    dmesg | tail
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        [ 5721.844355] bone-capemgr bone_capemgr.9: slot #7: 'Override Board Name,00A1,Override Manuf,BBB-RTC-01'
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        [ 5721.844607] bone-capemgr bone_capemgr.9: slot #7: Requesting part number/version based 'BBB-RTC-01-00A1.dtbo
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        [ 5721.844656] bone-capemgr bone_capemgr.9: slot #7: Requesting firmware 'BBB-RTC-01-00A1.dtbo' for board-name 'Override Board Name', version '00A1'
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        [ 5721.847380] bone-capemgr bone_capemgr.9: slot #7: dtbo 'BBB-RTC-01-00A1.dtbo' loaded; converting to live tree
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        [ 5721.848460] bone-capemgr bone_capemgr.9: slot #7: #3 overlays
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        [ 5721.860065] omap_i2c 4802a000.i2c: bus 2 rev0.11 at 100 kHz
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        [ 5721.902076] rtc-ds1307 2-0068: rtc core: registered ds1338 as rtc1
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        [ 5721.902147] rtc-ds1307 2-0068: 56 bytes nvram
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        [ 5721.902274] omap_i2c 4802a000.i2c: unable to select pin group
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        [ 5721.902468] bone-capemgr bone_capemgr.9: slot #7: Applied #3 overlays.
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</code>
  
  
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* Read the time from the RTC chip. It should look like something below since the time has not been set:
 +
<code>
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    hwclock -r -f /dev/rtc1
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    Sat 01 Jan 2000 12:06:17 AM UTC  -1.004531 seconds
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</code>
  
  
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==Revision Changes==
+
* Update the system time of the BeagleBone Black (internet connection required) and write that to the RTC chip using hwclock command:
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===Revision A1===
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<code>
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Initial release of RTC Cape.
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    ntpdate -b -s -u pool.ntp.org
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    hwclock -w -f /dev/rtc1
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</code>
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 +
 
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* Read the time again. This time it should have been updated.
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<code>
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    hwclock -r -f /dev/rtc1
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    Fri 16 May 2014 10:57:12 PM UTC  -0.755959 seconds
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</code>
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==Helpful Links==
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* [http://datasheets.maximintegrated.com/en/ds/DS1338-DS1338Z.pdf DS1338 Datasheet]
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* [http://elinux.org/Capemgr Capemgr wiki]
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* [http://www.devicetree.org/Device_Tree_Usage Device Tree Usage]
  
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==Software Support & Compatibility==
 
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All revisions are compatible with BeagleBone and BeagleBone Black using 3.8 kernel.
 
  
  
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Device tree overlay is coming soon.
 
  
  
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|I2C1_SDA
 
|I2C1_SDA
 
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|-
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|Multi-Function Pin
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|Squarewave Output Pin
 
|GPIO1_29
 
|GPIO1_29
 
|}
 
|}
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==Product Images==
 
==Product Images==
 
<gallery>
 
<gallery>
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File:RTCCape650.jpg|Generic Proto Cape
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File:RTC-SlantedTop650.jpg|RTC Cape
 
</gallery>
 
</gallery>
  
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==Documentations==
 
==Documentations==
 
====RTC Cape Revision A1====
 
====RTC Cape Revision A1====
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Coming soon.
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* [https://github.com/CircuitCo/RTC-Cape/blob/rev_a1/RTC_Cape_A1_BOM.xlsx?raw=true Bill of Materials]
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* [https://github.com/CircuitCo/RTC-Cape/blob/rev_a1/RTC_Cape_A1_Gerbers.zip?raw=true Manufacturing Files]
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* [https://github.com/CircuitCo/RTC-Cape/blob/rev_a1/RTC_Cape_A1_Schematic.pdf?raw=true Schematic (PDF)]
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* [https://github.com/CircuitCo/RTC-Cape/blob/rev_a1/RTC_Cape_A1.sch Schematic (EAGLE)] (Right click and save as...)
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* [https://github.com/CircuitCo/RTC-Cape/blob/rev_a1/RTC_Cape_A1.brd PCB (EAGLE)] (Right click and save as...)
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To download all files at once please click [https://github.com/CircuitCo/RTC-Cape/archive/rev_a1.zip here]
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To go back to the cape list, please click [http://elinux.org/Beagleboard:BeagleBone_Capes here]

Latest revision as of 07:57, 1 August 2017

Descriptions

RTC Cape

The RTC Cape provides time tracking capability for the BeagleBone Black even when the power is lost. This cape features the DS1338 I2C-based real-time clock/calendar and a holder for a coin battery type CR2032. Setup, reading, and setting up time is easy with the provided device tree overlay.









Revision Changes

Revision A1

Initial release of RTC Cape.



Software Support & Compatibility

  • All revisions are compatible with BeagleBone and BeagleBone Black using 3.8 kernel.
  • Latest software for BeagleBone Black can be downloaded here.



Getting Started

The instructions below are performed on Debian release 2014-05-14 (Linux beaglebone 3.8.13-bone50 #1 SMP Tue May 13 13:24:52 UTC 2014 armv7l GNU/Linux).

  • Connect your BeagleBone Black to the internet, log in as root, download the device tree files and extract them to /lib/firmware of your BBB:

   cd /lib/firmware
   wget https://github.com/CircuitCo/RTC-Cape/raw/docs/BBB-RTC-01-00A1.tar.gz
   tar xvzf BBB-RTC-01-00A1.tar.gz


  • Load the device tree overlay for your RTC Cape:

   echo BBB-RTC-01:00A1 > /sys/devices/bone_capemgr*/slots


  • Check to ensure the overlay is loaded. In the messages below, the DS1338 is registered as rtc1:

   dmesg | tail
       [ 5721.844355] bone-capemgr bone_capemgr.9: slot #7: 'Override Board Name,00A1,Override Manuf,BBB-RTC-01'
       [ 5721.844607] bone-capemgr bone_capemgr.9: slot #7: Requesting part number/version based 'BBB-RTC-01-00A1.dtbo
       [ 5721.844656] bone-capemgr bone_capemgr.9: slot #7: Requesting firmware 'BBB-RTC-01-00A1.dtbo' for board-name 'Override Board Name', version '00A1'
       [ 5721.847380] bone-capemgr bone_capemgr.9: slot #7: dtbo 'BBB-RTC-01-00A1.dtbo' loaded; converting to live tree
       [ 5721.848460] bone-capemgr bone_capemgr.9: slot #7: #3 overlays
       [ 5721.860065] omap_i2c 4802a000.i2c: bus 2 rev0.11 at 100 kHz
       [ 5721.902076] rtc-ds1307 2-0068: rtc core: registered ds1338 as rtc1
       [ 5721.902147] rtc-ds1307 2-0068: 56 bytes nvram
       [ 5721.902274] omap_i2c 4802a000.i2c: unable to select pin group
       [ 5721.902468] bone-capemgr bone_capemgr.9: slot #7: Applied #3 overlays.


  • Read the time from the RTC chip. It should look like something below since the time has not been set:

   hwclock -r -f /dev/rtc1
   Sat 01 Jan 2000 12:06:17 AM UTC  -1.004531 seconds


  • Update the system time of the BeagleBone Black (internet connection required) and write that to the RTC chip using hwclock command:

   ntpdate -b -s -u pool.ntp.org
   hwclock -w -f /dev/rtc1


  • Read the time again. This time it should have been updated.

   hwclock -r -f /dev/rtc1
   Fri 16 May 2014 10:57:12 PM UTC  -0.755959 seconds



Helpful Links



Specifications

Followings are some specifications of the RTC Cape:

Mechanical Specifications

Size 2.15" x 2.825"
Layers 2
PCB Thickness .062"
RoHS Compliant Yes



Signal Usage

RTC Cape
Power VDD_3V3EXP
I2C I2C1_SCL
I2C1_SDA
Squarewave Output Pin GPIO1_29



Distributors

Please visit Where To Buy for a list of distributors who carry BeagleBoardToys' capes.



Product Images

  • RTC Cape



Documentations

RTC Cape Revision A1

To download all files at once please click here


To go back to the cape list, please click here

Retrieved from "https://elinux.org/index.php?title=RTC_Cape&oldid=447611"