SPI Example for IMXRT 1020 EVK (Reason to remove R293 ?)

[narenchandra401]

Hello community ,

As i  was going through the SPI example from SDK  for IMXRT 1020 EVk , i have seen this in the read me Document .

Board settings
==============
Remove R293
SPI one board:
Transfer data from one board instance to another board's instance.
SPI1 pins are connected with SPI1 pins of another board
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
MASTER connect to SLAVE
Pin Name Board Location Pin Name Board Location
SOUT J19-4 SIN J19-5
SIN J19-5 SOUT J19-4
SCK J19-6 SCK J19-6
PCS0 J19-3 PCS0 J19-3
GND J19-7 GND J19-7
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

What is the real reason to remove R293 ?

As i see in the schematic this R293 is connected to SDRAM . and GPIO_EMC_14 is the pad number . 

Attaching pictures for clarity 

Although GPIO_EMC_14 - ALT 4 has SPI mux option ,  in the SDK it was not selected 

Pad Name

PIN No

Default Functionality

ALT0

ALT1

ALT2

ALT3

ALT4

ALT5

ALT6

ALT7

ADC1 I/P

ADC2 I/P

GPIO_EMC_14

1

GPIO2.IO[14]

SEMC_BA1

XBAR_INOUT14

LPUART6_CTS_B

SAI1_RX_BCLK

LPSPI2_PCS1

GPIO2.IO[14]

FLEXCAN1_TX

In SDK these pins were selected 

IOMUXC_SetPinMux(
IOMUXC_GPIO_AD_B0_10_LPSPI1_SCK, /* GPIO_AD_B0_10 is configured as LPSPI1_SCK */
0U); /* Software Input On Field: Input Path is determined by functionality */
IOMUXC_SetPinMux(
IOMUXC_GPIO_AD_B0_11_LPSPI1_PCS0, /* GPIO_AD_B0_11 is configured as LPSPI1_PCS0 */
0U); /* Software Input On Field: Input Path is determined by functionality */
IOMUXC_SetPinMux(
IOMUXC_GPIO_AD_B0_12_LPSPI1_SDO, /* GPIO_AD_B0_12 is configured as LPSPI1_SDO */
0U); /* Software Input On Field: Input Path is determined by functionality */
IOMUXC_SetPinMux(
IOMUXC_GPIO_AD_B0_13_LPSPI1_SDI, /* GPIO_AD_B0_13 is configured as LPSPI1_SDI */
0U); /* Software Input On Field: Input Path is determined by functionality */

I have dumped the SDK example in the evk and  checked if the clock is coming , but i only see 6 pulses instead of 8 . 

I completely have no idea why R293 was asked to be removed since that pin is not selected in the SDK , just wanted to know is not removing it is affecting my clock ?

Any response relevant will be most helpful .

Expecting a quick response , 

Thanks and Regards 

Naren Chandra 

[kerryzhou]

Hi Naren chandra ，

    Which detail project you are referring to?

   I check the following project:

    SDK_2.7.0_EVK-MIMXRT1020\boards\evkmimxrt1020\driver_examples\lpspi\interrupt

  This project readme didn't mention the remove R293.

   But I really find some other project mentioned it.

   My own opinion is it should be the readme bug.R293 should not influence the SPI project funtion.

    Do you test the SPI project directly without remove R293, do you meet any issue?

Kerry

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