DIY SZP wiring and firmware

oliof

Ever since the original pre-announcement of the Scanning Z probe, I got ahold of an LDC1612 to make use of a Sammy C21 board I bought ... a while back.

I browsed the forum, but didn't find the answer to some open questions:

a) Since the Duet3D scanning probe runs on a SAMC21 chip, can I use the SZP firmware on the SammyC21? I assume the bootloader may not take the wrong firmware (unless renamed maye)?

b) Is there a wiring diagram for a DIY SZP, i.e. how would I need to wire up the LDC1612 control board to the Sammy C21?

dc42

@oliof yes you should be able to use a LDC1612 with a SammyC21. I updated the standard SammyC21 build of Duet3Expansion firmware to support a LDC1612 but this has not been tested.

The pin connection are defined in file src/Config/SAMMYC21.h. In brief they are:

SCL -> PA23
SDA -> PA22
INT -> PA21

PS - I have just updated https://docs.duet3d.com/en/Duet3D_hardware/Duet_3_family/Using_the_Sammy-C21_development_board_with_Duet_3#features-of-the-standard-firmware-binary.

oliof

EDIT: Solved (thanks @jay_s_uk), I need

M558 K0 P11 C"120.i2c.ldc1612" F25000 T30000

(this printer has only z endstops, not another probe)

@dc42 I got the Sammy C21 up and running after some trials and tribulations, but with the 3.5.0-rc2 firmware, I cannot setup the SZP.

M558 P11 C"120.pa22+120.pa23" ; Board ID changed to match SZP default
Error: M558: expansion boards do not support Z probe output ports

(I know you did some more recent changes but I cannot currently rebuild my own since eclipse fails at start with a stupid SWT image loader error, and my Java is too rusty to sort this out, so I am trying to get somewhere with the currently released file).

oliof

M122 tells me the probe is up and running (amplitude error because the coil is off the bed)

M122 B120
Diagnostics for board 120:
Duet SAMMYC21 firmware version 3.5.0-rc.2 (2023-12-14 08:58:19)
Bootloader ID: not available
All averaging filters OK
Never used RAM 5708, free system stack 142 words
Tasks: Move(3,nWait,0.0%,135) HEAT(2,nWait,0.1%,135) CanAsync(5,nWait,0.0%,71) CanRecv(3,nWait,0.0%,79) CanClock(5,nWait,0.0%,67) MAIN(1,running,94.3%,426) IDLE(0,ready,0.0%,27) AIN(2,nWait,5.5%,92), total 100.0%
Last reset 00:00:10 ago, cause: power up
Last software reset data not available
Driver 0: pos 0, 80.0 steps/mm, steps req 0 done 0
Moves scheduled 0, completed 0, in progress 0, hiccups 0, segs 0, step errors 0, maxLate 0 maxPrep 0, maxOverdue 0, maxInc 0, mcErrs 0, gcmErrs 0, ebfmin 0.00 max 0.00
Peak sync jitter 2/10, peak Rx sync delay 195, resyncs 0/0, no timer interrupt scheduled
MCU temperature: min 25.4C, current 25.6C, max 25.6C
Last sensors broadcast 0x00000000 found 0 34 ticks ago, 0 ordering errs, loop time 0
CAN messages queued 103, send timeouts 0, received 191, lost 0, errs 0, boc 0, free buffers 18, min 18, error reg 0
dup 0, oos 0/0/0/0, bm 0, wbm 0, rxMotionDelay 0
Accelerometer: none
Inductive sensor: raw value 44678257, frequency 3.33MHz, current setting 13, amplitude error
I2C bus errors 0, naks 12, contentions 0, other errors 0

dc42

@oliof you will need to increase the drive current, see M558.2.

oliof

@dc42 I've yet to design a proper way to mount my rat's nest of components, the amplitude error goes away when I hold the coil some millimeters above the print bed.

Considering the individual cost of a Sammy C21, LDC1612, and an accelerometer, the SZP is both cheaper and more convenient (-: