SPI MISO Signal is always low

[jiehunt]

I use the i.mx sabreauto board to communicate to the slave board with SPI interface.

But, I cannot get the data from the slave.

I use oscilloscope to check the MISO signal, and this is always be LOW.

The same slave board works fine with raspberrypi.

Please, give some hint about this issue.

My environment is:

Linux version is Linux version 4.1.15-1.1.1

CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7)

And I checked the iomux register 

IOMUXC_SW_MUX_CTL_PAD_CSI0_DATA06　→　data：0x02

IOMUXC_SW_PAD_CTL_PAD_CSI0_DATA06　→　data：0x100B1

IOMUXC_ECSPI1_MISO_SELECT_INPUT　  →　data：0x03

I think is fine for spi transfer.

Thank you.

[jiehunt · Accepted solution]

 I use the other I.MX6 board and run the same program, the program works.

So, I think My Board has some problem.