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greenlantern01's avatar
greenlantern01
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3 months ago

LTC Connector DE10-Standard FPGA

I am trying to access the I2C bus on the LTC connector on the DE10 Standard FPGA board.  I have enabled the i2c controllers on the HPS. How do I now gain access to the i2c2 pins that are connected ...
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Programmable Logic Device
greenlantern01's avatar
greenlantern01
Icon for Occasional Contributor rankOccasional Contributor
1 month ago

Hi Kian,

I was wondering if you got a chance to have a look into this. 

Any help would be highly appreciated!

Regards

KianHinT_altera's avatar
KianHinT_altera
Icon for Frequent Contributor rankFrequent Contributor
1 month ago

Hi greenlantern01,

Really sorry for the delay in getting back, was going through my mails after back to office , missed out on the notification.   

From the screenshot, seems it is resetting during kernel loading stage, probably some settings in the dts.

 

I was checking back on Terasic schematic and notice that there is some differences between DE10-Standard Rev C and Rev D board. Could you help confirm you board revision ( i suppose to be rev C because in schematic I still see the digital accelerometer and HPS_LTC_GPIO connected to TS3A5018, Rev D schematic all these been removed)

 

Anyway if you're on Rev C, disregard the DTS changes you made first, and

1. Measure the HPS_LTC_GPIO ( can probe R306 resistor and check whether it toggles or switch just to check the pin logic )

I got this from the TS3A5018 datasheet (but the table here seems to indicate the other way round for NO/NC)

 

From schematic, Gsensor/ digital accelerometer is connected to I2C1 which looks like it is connected to different pin all together , not via TS3A5018 , thus you always can talk to Gsensor regardless of the LTG connector.

 

 

After verifying the LTC_GPIO toggles correctly, probably can check whether Linux side have these i2C drivers already initialized, if yes maybe no need add the i2c2 in the DTS for linux-socfpga

 

Try this command to list the i2c :   i2cdetect -l

You should see something like Synopsys DesignWare

 

scan the bus to see whether gsensor and your ltc shows up

i2cdetect -y -r <bus number from the list, 0,1,2>

 

This one to confirm that i2c has gsensor and your LTC device connected.

 

Thanks

Regards

Kian

  • greenlantern01's avatar
    greenlantern01
    Icon for Occasional Contributor rankOccasional Contributor
    1 month ago

    Hello Kian,

    Thank you for your response.

    1. It is revision C. However, it seems I've been referring to the schematics of rev b all this time. I could find only rev b schematics on the Terasic website. Could direct me to where I could find data on rev c boards?
    2. I wrote a c code for toggling the GPIO and probed the R306, however, there's no change. It doesn't toggle. It stays high. 
    3. When scanning the i2c bus, I see 0x53 which is the g-sensor since that is its device address. I don't see LTC connector.

    Regards

    • KianHinT_altera's avatar
      KianHinT_altera
      Icon for Frequent Contributor rankFrequent Contributor
      1 month ago

      Hi greenlantern01,

      Regarding the GPIO toggling not working , probably you can check whether R306 is the same placement as per rev C. Unfortunately i dont have Rev B schematic so cannot confirm on this whether the connections are the same with Rev C.

       

      Probably you will need to toggle the LTC first before can use the i2cdetect.

       

      Thanks

      Regards

      Kian

      • greenlantern01's avatar
        greenlantern01
        Icon for Occasional Contributor rankOccasional Contributor
        14 days ago

        Hi Kian,

        The board I am using is Rev C. I have tried doing the following steps to be able to toggle the HPS_LTC_GPIO:

        1. Verified the HDL file connections.

        2.  Checked the Pin Planner to confirm if I am connecting to the correct I2C bus.

        3. I generated the rbf file from the sof_to_rbf generator and saved it on the memory card which has angstrom on it.

        4. I have attached the C code that I used to toggle the HPS_LTC_GPIO.

        5. i2cdetect -l output:

        6. i2cdetect -y -r 0 output:

        I have shared the DTS file changes previously, however when trying to boot the FPGA after those changes the FPGA crashes.

        Despite these process I am still not able to toggle. Kindly advice on next steps. 

        Thanks