I2C1 not functional?

    Dear support,


    I'm trying to connect an external i2c device to I2C1 on an Armstone IMX8MP board.


    I have the following i2c configuration in my dtsi file (I only changed the clock frequency in the original dtsi from 400K to 100K):


    &i2c1 {

    clock-frequency = <100000>;

    pinctrl-names = "default";

    pinctrl-0 = <&pinctrl_i2c1>;

    status = "okay";


    pinctrl_i2c1: i2c1grp {

    fsl,pins = <

    MX8MP_IOMUXC_I2C1_SCL__I2C1_SCL 0x400001c3

    MX8MP_IOMUXC_I2C1_SDA__I2C1_SDA 0x400001c3

    >;

    };


    The corresponding pins 29 (I2C_D_SDA) and 31 (I2C_D_SCL) are routed externally to our interface board on which an i2c chip (a TI PCF8574A) is mounted which has address 0x38. However, when monitoring the addresses using the command i2cdetect -y 0, I have the following (note I disabled RTC and AD converter driver):


    0 1 2 3 4 5 6 7 8 9 a b c d e f

    00: -- -- -- -- -- -- -- --

    10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

    20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

    30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

    40: -- -- -- -- -- -- -- -- -- 49 -- -- -- -- -- --

    50: -- 51 -- -- -- -- -- -- -- -- -- -- -- -- -- --

    60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

    70: -- -- -- -- -- -- -- --

    Unfortunately I don't see address 0x38 appearing in the list.

    I crosschecked from a hardware perspective almost everything, but to no avail, the


    Am I overlooking something here?


    Thanks for your support,


    Didier Guillemyn.

    Hello Didier,


    what is the serial number of your board?

    Assume your board variant is configured for AIN and not for I2C_D becauce address=0x49 belongs to ADS1015 (ADDR=high).

    F&S Elektronik Systeme GmbH
    As this is an international forum, please try to post in English.
    Da dies ein internationales Forum ist, bitten wir darum, Beiträge möglichst in Englisch zu verfassen.

    Hi Didier,


    yes this it the right number. So I figure out your baord is configured for AIN not for I2C_D.


    a) You can send use the board(s) as RMA for conversation (add these post as referee).

    b) I can send you conversation instructions in a separate private mail if desired. You have to remove ADS1015 and add two jumpers. Note, warranty voids if you do this.

    F&S Elektronik Systeme GmbH
    As this is an international forum, please try to post in English.
    Da dies ein internationales Forum ist, bitten wir darum, Beiträge möglichst in Englisch zu verfassen.

    Hi,


    Thanks for the quick response.


    Before we get into an RMA, some questions:


    1. can you explain me what AIN stands for, what is its purpose?

    2. do we have a one-off board or do all the armStoneMX8MP-V22I-LIN SBC's have this AIN on board?

    3. if all the armStoneMX8MP-V22I-LIN do have AIN on board, is there another armStoneMX8MP variant that does not have the AIN?

    4. An alternative is to use another I2C, i.e. I2C4 (on pins 8 / 10). Is this I2C available for our use?


    Note the expansion board on which the I2C TI PCF8574A is mounted is a board currently designed in combination with an ArmstoneA9r3 (WEC7). We obviously want to avoid as much as possible a redesign of this expansion board. Moreover we are still evaluating which armStoneMX8MP variant is best suited for our application, so all of above questions are relevant in our hardware evaluation and redesign process.

    Hi Didier,


    first - an additional question from my side. Your expansion board where I2C TI PCF8574A is mounted works currently in combination with an ArmstoneA9r3? That's stange! As far as I see (all) previous armStones have no I2C option at all on FC.29, FC.31 (refer HW doc). There is only AIN available. Else please provide me the serial number of ArmstoneA9r3 so that I can double check.


    >>1. can you explain me what AIN stands for, what is its purpose?

    << Analog Input (ADConverter). There are ADS1015 mounted and AIN0...3 available on FC.29, FC.31, FC.33, FC.35.


    >> 2. do we have a one-off board or do all the armStoneMX8MP-V22I-LIN SBC's have this AIN on board?

    >> 3. if all the armStoneMX8MP-V22I-LIN do have AIN on board, is there another armStoneMX8MP variant that does not have the AIN?

    << Part number "armStoneMX8MP-V22I-LIN" do have AIN on board. It is no problem to create a part number with I2C_D option. Please contact our sales office for this purpose.


    >> 4. An alternative is to use another I2C, i.e. I2C4 (on pins 8 / 10). Is this I2C available for our use?

    << Sorry, these pins confugured as SPI in part number "armStoneMX8MP-V22I-LIN"! We have to move some jumpers too in this case to use I2C instead of SPI.

    What is about I2C_C (FC.19, FC21). These pins seems to have the I2C option not UART_B_RTC/CTS;).

    F&S Elektronik Systeme GmbH
    As this is an international forum, please try to post in English.
    Da dies ein internationales Forum ist, bitten wir darum, Beiträge möglichst in Englisch zu verfassen.

    Hi,


    1. Indeed some clarification on the expansion board in combination with ArmstoneA9R3: I was not fully correct in my statement: the original board had it wired to pin 16 and 17 of the ArmstoneA9R3 board. We meanwhile already rewired a prototype of our new expansion board to pin 29 and 31.

    2. On "Part number "armStoneMX8MP-V22I-LIN" do have AIN on board. It is no problem to create a part number with I2C_D option. Please contact our sales office for this purpose." If we can have such a variant without extra costs, that's an option.

    3. On "Sorry, these pins confugured as SPI in part number "armStoneMX8MP-V22I-LIN"! We have to move some jumpers too in this case to use I2C instead of SPI. What is about I2C_C (FC.19, FC21). These pins seems to have the I2C option not UART_B_RTC/CTS;" That's another option, but we will need to reroute in this case some GPIO pins on our expansion board that are now using FC19 / FC21.


    I'll crosscheck these options with our hardware engineer.


    Thanks and regards,


    Didier.