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I2C MCP7941x

Library containing support for battery backed SRAM support provided by realtime clock MCP7941x.

Changelog

v0.0.2.1 under construction

devdescr.xml: vendor id set to 0003, device id set to 0009, see https://forge.codesys.com/drv/io-drivers/database/Home/ for details. 

    <DeviceIdentification>
      <Type>500</Type>
      <Id>0003 0009</Id>
      <Version>0.0.2.1</Version>
    </DeviceIdentification>

v0.0.0.1 initial version

i2c address setting

install i2c tools

sudo apt-get update
sudo apt-get install i2c-tools

MCP7941x i2c address and resources check

Be sure the MCP7941x is attached.

  • run "sudo i2cdetect -y 0" => You should now see a table with the connected i2c slave address.
  • If "sudo i2cdetect -y 0" does not work, then run "sudo i2cdetect -y 1", this is Pi model dependant.
aliazzz@Raspbian:~ $ sudo i2cdetect -y 1
      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- 18 -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- 57 -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 6f
70: -- -- -- -- -- -- -- --

If "UU" shows in the table, probing was skipped because this address is currently in use by a driver.
This strongly suggests that there is a chip at this address. The UU means that the I2C address is already being used by some other bit of software.
Above the RTC (6f) is readily available for CODESYS