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MATRIX7878
Associate II
October 21, 2024
Solved

Square wave output M48T201V

Hello,

 

     I am trying to test out my TIMEKEEPERS square wave output.  I set my frequency, then enable.  However, I do not get a signal out.  The SNAPHAT is attached to the IC, so I am not sure what is wrong.  Do I need to read after every write, restart the crystal, something else?  If anybody knows what to do, I appreciate some guidance.

 

Thank you

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Tesla DeLorean
Tesla DeLoreanBest answer
Guru
November 25, 2024

>>It has been over a month and I have not received any replies

The pool here is pretty shallow. You're swimming by yourself. It's a 15 year old part design, the staff that designed / supported this are likely doing other things these days.

 

TM4C129EXL ? The code could probably do with using tables. I'm not sufficiently familar with the board design or MCU to confirm if the pin usage, or timing, nor what you're actually reading/writing into the MT48T201V.

You're not providing a dump of any of the RTC/Timing registers/memory locations

You'd need to select a frequency for the output RS3-RS0 (0x7FFF0), and enable via SQWE (0x7FFF6). Check you can read/write the registers successfully.

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7 replies

MATRIX7878Author
Associate II
November 24, 2024

Hello,

 

     It has been over a month and I have not received any replies.  I am still having the same issue.  Could it be my crystal?  Or my code?

 

Thank you.

AScha.3
AScha.3
Super User
November 24, 2024

Hi,

I can only say for myself: I have no idea, what you doing and what not working as you expect.

Timekeeper Snapchat or something...

If you explain what CPU, board and program you use, then what it should do and then what not working.... maybe some answers coming.

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    MATRIX7878Author
    Associate II
    November 25, 2024

    Hello,

     

         What I really need is an example of how to use the square wave output.  My code is attached so you can see.  I am using a TM4C129EXL.  The code 1st tests the SRAM chip and then sends out a square wave output.  I am not sure if my code is wrong, or if the crystal does not work.

     

    Thank you

    MATRIX7878Author
    Associate II
    November 25, 2024

    Hello,

     

         Oh.  That makes sense.  I will manage my expectations.

     

         Yes, that is my main microcontroller.  I am not sure what tables I could use.  I create an array of addresses from 0x7FFF0 to 0x7FFFF.  I am writing the address and then I write the data.  I know the pins are right since I can write and read to the SRAM.

     

         I cannot get a dump of the SRAM chip itself and getting a dump of the program is a challenge in and of itself.  I attached a screenshot of the active memory area.  I'm not sure if you will get much out of it though.  If you have any more detail about what you need, I'll send that to you.

     

         I do, do that.  I start off by writing 0x01 to 0x7FFF0 and then enable it by writing 0x40 to 0x7FFF6.  I tried to do a logic analyzer of the board, but the data gets corrupted.  The logic analyzer somehow messes the signals up.

     

    If you need anything else, or have a code example, I would appreciate it.

     

    Thank you

    MATRIX7878Author
    Associate II
    November 30, 2024

    Hello,

     

         I figured out my problem.  I forgot to turn the data pins back to write to write to the chip.  Wow I can be *** at times.  Thank you all for your help.

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