This tool modifies SPI or GPIO state in a way that confuses Klipper

[Xaphiosis]

Before running this tool, an ADXL345 connected to a Raspberry Pi running Klipper can do this:

ACCELEROMETER_QUERY CHIP=hotend
accelerometer values (x, y, z): -222.061783, 518.144159, -10418.898773

After running adxl345spi (which works, and returns values), we get:

Invalid adxl345 id (got 0 vs e5).
This is generally indicative of connection problems
(e.g. faulty wiring) or a faulty adxl345 chip.

Unplugging/replugging the ADXL345 board is not sufficient to get it working again. Without better understanding of what's been changed, I have to reboot the pi to be able to use accelerometers with Klipper again.

I'm not sure whether it's possible or convenient to save whatever state is being changed and restore it when adxl345spi terminates, but it would be nice for cases like this. I acknowledge that most likely Klipper should set whatever state this is to its liking, but as I don't know what that is, I'm hoping for an answer here.

[Quas7]

Restarting the klipper service itself does not setup the spi again? That would be odd.

[Xaphiosis]

I can confirm that sudo service klipper restart does not resolve the issue. Maybe it's a but on the klipper side, but to make an issue there I'd have to have a clue what's being persistently changed here.

[Quas7]

My first guess would be SPI bus frequency. This should be a commandline parameter as far as I see and can be set to match klippers.

[nagimov]

@Xaphiosis could you play with setting different SPI bus speeds here

adxl345spi/adxl345spi.c

Line 20 in a05f03a

const int speedSPI = 2000000; // SPI communication speed, bps

and see if there's a value that resolves klipper compatibility?

[Xaphiosis]

@nagimov
I've tried to look into this as far as I'm able, but have not found any enlightenment. Regarding the SPI bus speed, as far as I can tell Klipper does this:

    speed = config.getint('spi_speed', default_speed, minval=100000)

so I set the speed in my config to be the same as your tool, i.e. 2000000 in my config:

[adxl345 hotend]
spi_speed: 2000000
cs_pin: rpi:None
spi_bus: spidev0.0

[adxl345 bed]
spi_speed: 2000000
cs_pin: rpi:None
spi_bus: spidev0.1

Unfortunately, this does not help. The error occurs in klippy/extras/adxl345.py here:

    def _start_measurements(self):
        # In case of miswiring, testing ADXL345 device ID prevents treating
        # noise or wrong signal as a correctly initialized device
        dev_id = self.read_reg(REG_DEVID)
        if dev_id != ADXL345_DEV_ID:
            raise self.printer.command_error(
                "Invalid adxl345 id (got %x vs %x).\n"
                "This is generally indicative of connection problems\n"
                "(e.g. faulty wiring) or a faulty adxl345 chip."
                % (dev_id, ADXL345_DEV_ID))

and indeed, trying to do ACCELEROMETER_DEBUG_READ CHIP=hotend REG=0 (up to REG=44 where I stopped trying) returns 0x0

The error occurs before they try to set any other ADXL345 configuration:

        # Setup chip in requested query rate
        self.set_reg(REG_POWER_CTL, 0x00)
        self.set_reg(REG_DATA_FORMAT, 0x0B)
        self.set_reg(REG_FIFO_CTL, 0x00)
        self.set_reg(REG_BW_RATE, QUERY_RATES[self.data_rate])
        self.set_reg(REG_FIFO_CTL, SET_FIFO_CTL)

Trying to manually set the register with ACCELEROMETER_DEBUG_WRITE CHIP=hotend REG=0 VAL=0xe5 does not work (Failed to set ADXL345 register [0x0] to 0xe5: got 0x0).

Trying -f 3200 (since klipper expects 3200) doesn't do anything either.

Any other ideas what it could be?

[nagimov]

@Xaphiosis could you recompile with spiClose(h); before this return(0);

adxl345spi/adxl345spi.c

Line 287 in a05f03a

return 0;

and check if that helps?

[Xaphiosis]

Sadly it does not help. Tried updating all klipper-related packages on the pi, but that didn't change anything either.

My only idea is when I have a bit more time to go through adxl345spi.c and keep removing things until I can find a minimal set of operations which will trigger this.