LinuxCNC-RIO - RealtimeIO for LinuxCNC based on FPGA (ICE40 / ECP5)

M10x1 on my cnc conversion (HG125 C0 lathe) with 3D printed parts



works

I'm soooo happy
   

Display's and Encoder's
www.youtube.com/shorts/U16rtV2JOMA

Extreme - Jogging

Joypad + Encoder + MPG + Buttons at the same time (build by the hal-generator)

I have a raspberry pi5 and this is the code of how I started the SPI communication of the RPI5 - TangNano9K. (Not yet machine tested)

OS: 

• LinuxCNC 2.9.2  Raspberry Pi 5 OS based on Debian Bookworm  Raspberry Pi 5 Uspace compatible with Mesa Ethernet and SPI interface boards.

In /boot/broadcom/config.txt check is SPI is enabled (reboot if not)

# uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
dtparam=spi=on

In /dev/
Check do you have listed spidev0.0, should be!

In RIO.h define:

#define TRANSPORT_SPI5

In RIO C add lines:

#ifdef TRANSPORT_SPI5
#include <linux/spi/spidev.h>
#include <sys/ioctl.h>
#endif

/***********************************************************************
*                STRUCTURES AND GLOBAL VARIABLES                       *
************************************************************************/

#ifdef TRANSPORT_SPI5
int spifd;
static uint8_t mode = SPI_MODE_0;
static uint8_t bits = 8;
static uint32_t speed = 1500000;
#endif

/***********************************************************************
*                       INIT AND EXIT CODE                             *
************************************************************************/

#ifdef TRANSPORT_SPI5
    rtapi_print("Info: Initialize SPI5 connection\n");
    spifd = open("/dev/spidev0.0", O_RDWR);
    if (spifd < 0) {
        rtapi_print_msg(RTAPI_MSG_ERR,"Failed to open SPI device\n");
        return -1;
    }

    // Set SPI mode
    if (ioctl(spifd, SPI_IOC_WR_MODE, &mode) == -1) {
        rtapi_print_msg(RTAPI_MSG_ERR,"Failed to set SPI mode\n");
        close(spifd);
        return -1;
    }

    // Set bits per word
    if (ioctl(spifd, SPI_IOC_WR_BITS_PER_WORD, &bits) == -1) {
        rtapi_print_msg(RTAPI_MSG_ERR,"Failed to set bits per word\n");
        close(spifd);
        return -1;
    }

    // Set max speed
    if (ioctl(spifd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) == -1) {
        rtapi_print_msg(RTAPI_MSG_ERR,"Failed to set max speed\n");
        close(spifd);
        return -1;
    }
#endif

//Edit rtapi_app_exit function, add close(spifd)

void rtapi_app_exit(void)
{
    close(spifd);
    hal_exit(comp_id);
}

//In fuction void rio_transfer()  near end of it add: 

#ifdef TRANSPORT_SPI5

    struct spi_ioc_transfer tr = {
        //.tx_buf = (uint64_t)tx_buf,
        //.rx_buf = (uint64_t)rx_buf,
        .tx_buf = (uint64_t)txData.txBuffer,
        .rx_buf = (uint64_t)rxData.rxBuffer, 
        .len = SPIBUFSIZE,
        .speed_hz = speed,
        .delay_usecs = 0,
        .bits_per_word = bits,
    };

    // Perform SPI transfer
    if (ioctl(spifd, SPI_IOC_MESSAGE(1), &tr) == -1) {
rtapi_print_msg(RTAPI_MSG_ERR,"Failed to perform SPI transfer\n");
        //close(spifd);
        //return -1;
    }

#endif

//Save and do hallcompile...
 

Thanks,
I think the problem with RPI5 and SPI was that it is not realtime-capable. But I don't know exactly, I don't have an RPI5 yet.

I'm looking forward to the first machine tests

It's not so much it isn't "realtime capable" but since the SPI interface was moved to the RP1 chip, none of the former Rpi 4 code works.
Going thru /dev/spi doesn't appear to be fast enough, at least for the mesa cards.

Here is demo video: 
Since implementing this solution, I haven't experienced any communication issues. I can't say the same for previous tests where I used a laptop and a W5500 chip.

While researching the topic, I came across cases where people use spidev kernel libraries to manage several displays. They even mention 200Mhz clocks what is hard to believe. Official RPi pages stays on maximum 50Mhz. So speed should not be issue and "realtime capable" out of my understanding.  

I'm working on 1.5Mhz. I'm still learning and even don't know what is acceptable speeds. from orginal BMC library i extract some data that speed should be around 1.5Mhz.   

Playtime:

www.youtube.com/shorts/Ki7himYylcY

what the hell is wrong with me

www.youtube.com/shorts/tQvyrIP7aVc

but i have a serious problem with the kinematic, i need only 4joints, but the melfa stuff have 6
don't know how to setup a 4dof robot the right way