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.
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.