Can't get LPSPI example working on i.MXRT1064 EVK

[langrind]

I am using MCUXpresso with the i.MXRT1064 evaluation kit.

There is an SDK example called `evkmimxrt1064_lpspi_interrupt_b2b_master` which uses LPSPI (specifically LPSPI1.)

I don't have two boards, so instead I hooked up a logic analyzer. At this point, I just want to see the signals change state. The LPSPI master should be able to drive Chip Select low even if a slave isn't physically present.

When the example runs, the logic analyzer sees no activity on any of the four signals.

The i.MXRT1064 EVK brings `GPIO_SD_B0_00 - GPIO_SD_B0_03` out to J24 positions 6,3,4,5. 
 
To set up IOMUX control to use the above pins: 
 
  IOMUXC_SetPinMux( 
      IOMUXC_GPIO_SD_B0_00_LPSPI1_SCK,        /* GPIO_SD_B0_00 is configured as LPSPI1_SCK */ 
      0U);                                    /* Software Input On Field: Input Path is determined by functionality */ 
  IOMUXC_SetPinMux( 
      IOMUXC_GPIO_SD_B0_01_LPSPI1_PCS0,       /* GPIO_SD_B0_01 is configured as LPSPI1_PCS0 */ 
      0U);                                    /* Software Input On Field: Input Path is determined by functionality */ 
  IOMUXC_SetPinMux( 
      IOMUXC_GPIO_SD_B0_02_LPSPI1_SDO,        /* GPIO_SD_B0_02 is configured as LPSPI1_SDO */ 
      0U);                                    /* Software Input On Field: Input Path is determined by functionality */ 
  IOMUXC_SetPinMux( 
      IOMUXC_GPIO_SD_B0_03_LPSPI1_SDI,        /* GPIO_SD_B0_03 is configured as LPSPI1_SDI */ 
      0U);                                    /* Software Input On Field: Input Path is determined by functionality */  
 
Trying different pad configurations (pull up, drive strength) didn't make a difference.

I think I am missing something basic! Any advice appreciated.

Nik

[kerryzhou · Accepted solution]

Hi Nicholas Langrind ,

   Do you weld 0 ohm resistor to R278, R279,R280,R281?

  Where is the test point you have connected to your  logic analyzer ?

 No signal, should be caused by no connection to the RT chip related pins.

Wish it helps you!

Kerry

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[langrind]

Hi Kerry,

I did not look see the DNP on the schematic. This is the explanation.  Thanks very much.

(Hmm... I didn't read the example's documentation closely enough either. My bad.)

All the best,

Nik