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Original question:

AWR1243: Cascaded reference design I2C to SPI bridge

AWR1243: I2C to SPI bridge SC18IS602B address pin connection

Nishant G
Expert 1600 points
Part Number: AWR1243

Hello,

I am using a TDA2px( Master) to communicate with AWR1243( Slave) using FPD-Link connection. As AWR1243 supports only SPI communication and no I2C, I have used a SPI-I2C bridge SC18IS602B (same used by D3 for radar satellite configuration as mentioned in the original post) to convert the I2C Control to SPI Command for interfacing with radar sensor.

How should I connect the address pins A0, A1, A2 of the SPI-I2C bridge SC18IS602B? Should I connect them in pull up or pull down?  As per the datasheet of SC18IS602B, the three pins are used by Master for addressing the slaves. In my application, the master would be the TDA2px and the slaves would be the radar sensors AWR1243. But I do not know what the address of the slaves 1243 are as I believe AWR1243 supports only SPI communication. Hence, I am confused on what address are they referring to in the datasheet?

I look forward to your reply. Thank you!

Best Regards,

Nishant

  • 0
    TI__Mastermind 22155 points
    Hello Nishant,

    From my understanding you are referring to "www.ti.com/.../thirdpartydevtoolfolder.tsp .

    In this you have the AWR1243 connected to the I2C to SPI bridge and the address is already fixed. For the TDA2x the AWR1243 is a remote slave with adress of 0x40 (7 bit addressing) . Once you configure the de-serializer on the TDA2x you will be able to see the remote slaves connected to the TDA2x if you scan the I2C bus. You will see remote slave address of serializer, I2C-GPOI expander, I2C-SPI bridge.

    Could you please let me know what SW you are using to configure your HW?

    -Raghu
  • 0 in reply to Raghunandan Kamath
    Expert 1600 points

    Hello Raghu,

    Thank you for your answer! Yes, the hardware module link that you provided is the one that I was referring to and I am using Vision SDK 3.05 to configure HW. I am using TDA2Px, so will I have to modify anything in the SW? 

    Best Regards,

    Nishant

  • 0 in reply to Nishant G
    Expert 1600 points

    Hello Raghu,

    This is the snippet from the datasheet of SC18IS602B I2C to SPI converter. According to you, the default 7-bit address assigned to the AWR1243 Port 0 sensor is 0x40 (which I believe is defined by D3_AR1243_PORT_0_SENSOR_ADDR in "bsputils_ub960.h"). But if you look at the above image, the initial 4 bits are fixed, so shouldn't the addressing scheme start with 0x5x? Also, in the program the parameter D3_AR1243_PORT_0_SENSOR_ADDR is used to set the PORT 0- I2C-SPI bridge alias address when communicating with UB960 through I2C. Is it same as the sensor AWR1243 I2C address?

    I look forward to your reply. Thank you!

    Best Regards,

    Nishant

  • 0 in reply to Nishant G
    Expert 1600 points
    Hello Raghu,

    Wanted to ask one more question related to it. I was told about some voltage translator related to I2C-SPI bridge by my FAE. Could you please elaborate on that please as I don't have feedback related to the voltage translator.

    Best Regards,
    Nishant
  • 0 in reply to Nishant G
    TI__Mastermind 22155 points
    Nishant,
    The IO levels from the 953 are at 1.8V level while the IO levels from the I2C to SPI bridge is a 3.3V level. Based on the IO level of the AWR device module you may need level shifter at one of the paths.

    -Raghu
  • 0 in reply to Raghunandan Kamath
    Expert 1600 points

    Hello Raghu,

    Thank you for clarifying the Voltage translator question. I look forward to your help for the addressing pin setting A0, A1, A2 of SPI-I2C bridge (SC18IS602B) for the radar satellite configuration and communicating with radar sensor AWR1243 as well.

     

    Thank you!

    Best Regards,

    Nishant

  • 0 in reply to Nishant G
    Expert 1600 points

    Hello Raghu,

    This is the screenshot of the address pins from the datasheet that I found online for the SPI-I2C bridge SC18IS602.

    Based on the information provided above, I believe the address pins are used to set the I2C address of the SPI-I2C bridge SC18IS602, which is defined in the SDK package as 0X50. This means I would have to set the address pins A0, A1, A2 pulled down to ground (to make it zero) as the first nibble is fixed.(The address should be something 0x5X). Could you please confirm if I have done this correct?

    I look forward to your reply. Thank you!

    Best Regards,

    Nishant

  • 0 in reply to Nishant G
    TI__Mastermind 22155 points
    Nishant,

    Thanks for your patience.
    I am asking the right Radar SDK folks to address your query.

    -Raghu
  • 0 in reply to Raghunandan Kamath
    Expert 1600 points
    Hello Raghu,

    Thank you! I look forward to their answer.

    Best Regards,
    Nishant
  • 0 in reply to Nishant G
    TI__Guru 50045 points

    Hi Nishant,

    0x50 is indeed the slave address for I2C-to-SPI bridge chip and that is what we programmed into UB960 at register 0x5E.

    Please refer to the below line of code.

    {0x5E, 0x50, UB960_REG_DELAY_TIME}, /*I2C-SPI bridge I2C Address*/

    D3_AR1243_PORT_0_SENSOR_ADDR is the alias address TDA uses to talk to bridge chip thru UB960 and UB960 will translate that to the actual slave address programmed in the above register.

    We use the alias address on TDA side to differentiate multiple bridge chips which can have the same slave address.

    Regards,
    Stanley