Problem on T4240 thermal diode with ADT7481reading temperature.

[dhanasekaran]

Hi all!

      I read ADT7481 Temperature registers. From this i got only its local temperature as a correct reading but other two remote temperatures are always remains zero. According to the configuration register measurements happens round robin

method method and from data-sheet of T4240 thermal diodes are not functional one(de-featured). If am i right then the output i got zero(temperature) for remote temperate correct one so their is no thermal unit to use.

Please clarify my doubt thank you all!

            QorIQ T4240 Data Sheet, Rev. 1, 05/2016

               3.1.2 Recommended operating conditions

                        8. Keep this pin biased to the specified voltage, despite the thermal monitoring unit being de-featured.

[dhanasekaran · Accepted solution]

This problem solved by changing proper capacitor in the thermal IC.

Thanks.

[ufedor]

The on-die thermal diodes (external signals TD1_ and TD2_) do not belong to the Thermal Management Unit and are operational.

Which board is in question?

Note that on the T4240RDB the thermal diodes are connected to the W83793G (U6)  - and not to the ADT7481 (U2).

[dhanasekaran]

Hi!

Thanks for the reply, actually we refer T4240RDB for custom board in this we use ADT7481. This IC can reads temperature of all (local and remote) automatically by default as per the data-sheet But local temperature only updated others not i.e had value of zero. Is this(ADT7481) not capable of reading temperature from thermal diodes? that why is the T4240RDB use W83793G. or any suggestion to solve this problem and how check this function from Hardware site .

  Regards,

   dhanasekaran K.

[ufedor]

The ADT7481 is used on the T4240QDS board and there were no problems reported concerning its operation with internal thermal diodes of the T4240.

Please refer to the ADT7481 Data Sheet and check your software.

[dhanasekaran]

hi, This is my reading process,

I read ADT7481 from kernel and got below result,

i2cdump -y 1 0x4c b
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 21 00 88 00 07 55 00 55 00 00 07 55 00 55 00 00 !.?.+U.U..+U.U..
10: 00 00 00 00 00 00 00 00 00 55 00 00 00 00 00 00 .........U......
20: 55 0a 01 09 00 00 00 00 00 00 00 00 00 00 00 00 U???............
30: 00 55 00 00 00 00 00 00 00 55 00 00 00 81 41 02 .U.......U...?A?

Thanks

[dhanasekaran]

Hi and Thanks for the reply,

            can you share T4240QDS schematic for our reference i.e the connection is similar with T4241RDB schematic with ADT7481.

         can you tell me that any configuration should made in T4240 processor to work with thermal diode or by default it works and provide correspond output. if it is right how check processor output.

thanks and regards,

 dhanasekaran K

[ufedor]

The ADT7481 is identically connected on the RDB and QDS boards.

The QDS connection is:

The T4240 thermal diode can be verified/probed as any diode - by means of a multimeter.

[dhanasekaran]

Hi!

   Finally we got some meaningful result in remote temperature register after changed capacitor from 1uF to 1000pF.

Regards,

dhanasekaran K