2 2
Park Namsu

Orange pi zero Mainline kernel, SPI Clk is weird.

Recommended Posts

Hi.

Kernel version : 4.11.7-sun8i

 

My trouble is that clk is weird in using spidev. 

This is a oscilograph when i send a command with spi.

First line is CLK and second line is CS0.

image.png.6f4f7b24f3f7faedf7a7a17b20a2dcbd.png 

 

My slave chip can not receive commands.

and I think it due to this weird CLK. 

CS seems affect CLK.

 

I just want to use spi with CS keeping active-low.

But, following code setting mode of spi occured an error.  "invalid argument exception"  

	mode = SPI_MODE_1 | SPI_NO_CS; 
	if (ioctl(file,SPI_IOC_WR_MODE32,&mode)<0){
		perror("can't set spi mode");
		return;
	}

this work properly.

	mode = SPI_MODE_1; 
	if (ioctl(file,SPI_IOC_WR_MODE32,&mode)<0){
		perror("can't set spi mode");
		return;
	}

so i used this code setting spi_ioc_transfer.

	xfer[0].cs_change = 0; /* Keep CS activated */
	xfer[0].delay_usecs = 0, //delay in us
	xfer[0].speed_hz = 12000000, //speed
	xfer[0].bits_per_word = 8, // bites per word 8

but cs still work and affect clk. 

 

this is my /boot/armbianEnv.txt

verbosity=1
logo=disabled
console=both
disp_mode=1920x1080p60
overlay_prefix=sun8i-h3
rootdev=UUID=4d25b54f-cc4d-4215-93e3-b5e3868e5a06
rootfstype=ext4
overlays=uart1 uart2 spi-spidev
param_spidev_spi_bus=1
param_spidev_spi_cs=1

Thank you.

Share this post


Link to post
Share on other sites
Want Armbian t-shirt or a cup?

Guest
This topic is now closed to further replies.
2 2