Difference between revisions of "Jetson/RTC"

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! Adafruit  !! DealExtreme  !! Victory-Seven
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| [[File:Adafruite_ChronoDot_255-00.jpg|250px|Adafruit DS3231 RTC module]] || [[File:DX_sku_222910_1.jpg|250px|DealExtreme DS3231 RTC module]] || [[File:VictorySeven_REL-dS3231.jpg|250px|Victory-Seven DS3231 RTC module]]
 
| [[File:Adafruite_ChronoDot_255-00.jpg|250px|Adafruit DS3231 RTC module]] || [[File:DX_sku_222910_1.jpg|250px|DealExtreme DS3231 RTC module]] || [[File:VictorySeven_REL-dS3231.jpg|250px|Victory-Seven DS3231 RTC module]]
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| [http://www.adafruit.com/product/255 Product page] || [http://www.dx.com/p/ds3231-high-precision-real-time-clock-module-blue-3-3-5-5v-222910 Product page] || [http://victory7.com/?pid=71440082 Product page]
 
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Revision as of 18:20, 4 December 2014

Basic strategy

Simply follow Santyago's great How-To posted on the forum.

https://devtalk.nvidia.com/default/topic/769727/embedded-systems/-howto-battery-backup-rtc/

  • Use Santyago's Grinch Custom Kernel 19.3.4 or above
  • Use an RTC module (Dallas DS3231)
  • Connect the RTC module on Jetson TK1's I2C bus

Detail

Custom Kernel

Install Santyago's Grinch Custom Kernel.

https://devtalk.nvidia.com/default/topic/766303/embedded-systems/-customkernel-the-grinch-19-3-7-for-jetson-tk1/

RTC Module

In the How-To, Santyago shows how to wire Maxim's DS3231, a high precision I²C real-time clock (RTC) with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. While it is possible to get the chip and wire everything by yourself, it is easier to just get a module that has the same chip.

Adafruit DealExtreme Victory7
Adafruit DS3231 RTC module DealExtreme DS3231 RTC module Victory-Seven DS3231 RTC module
Product page Product page Product page

There seems to be couple of options. You can get an RTC module with DS3231 from Adafruit, DealExtreme and some other. DS1307 based RTC module might work, but have not tried.

I used a module from a shop in Japan, this one seems to be originally made for Raspberry Pi. The interface is simple. It's just I2C, so all you need to care is VCC, GND and pins for I2C (SCL and SDA).

Connection and Securing the module on the board

J3A1 I2C-highlighted.png

I made wiring from the RTC module to back of the J3A1 headers, so that you can still insert some other things for expansion. There are GND, VCC, SCL and SDA pins from Pin #14 to #20 of J3A1 header in one row.

Pin# on J3A1 RTC Module
GND 14 GND(1)
VCC 16 VCC(4)
SCL 18 SCL(3)
SDA 20 SDA(2)

The RTC module from Victory7 had a 2.54mm-pitch 4-pin header to go into a breadboard. I took them out for easy mounting. (Wish this in 2mm-pitch and in the same order as pins on the J3A1 header)

RTC wired-to-the-bottom.JPG

RTC how-to-paste.JPG

RTC module-mounted-on-top.JPG