Unable to Parse UART Address !0 on Duet 3

General Discussion
1

Basic Information:

Printer Model: Custom
MCU / Printerboard: Duet 3 Mini 5+
Host / SBC: Raspberry Pi 4 8GB
klippy.log

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Describe your issue:

I’ve been having an issue with the uart_address field while configuring the [tmc2209 stepper_x].

I’ve started with the generic-duet-3-mini.cfg, and have been making the necessary configuration tweaks. However, I’ve been unable to connect to any tmc2209 drivers that have a uart address other than 0, 1, 2, or 3.

According to the commented instructions, drivers 4 through 6 should be addressed as !0, !1, and !2.

However, Klipper appears to be unable to parse this properly. I tried -1 and 4, but they didn’t work either.

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It looks like I am not the first one with this problem, but annoyingly, the discussion ended with a statement that they had solved it over Discord, and no solution was provided in the thread.

The dual-z and dual-y motor drivers (0, 1, 2, 3) seem to be doing absolutely fine, and I have reliably been able to tweak the current. The x-axis moves, but its stepper is literally too hot to touch after about a minute.

(And yes, stepper_x is driver 4. Long story.)

Any help would be greatly appreciated.

klippy.log (3.7 MB)

2

New users are apparently only allowed one link per post, so I wasn’t able to include the generic-duet3-mini.cfg. Here it is now.

3

Apologies for the absurdly long log file. I’ve tried a bunch of different things since I last booted it up. The relevant config stuff should be near the bottom.

4

Hello @bagsley3 !

[tmc2209 extruder]
uart_pin = PA1
tx_pin = PA0
uart_address = !0    # <=================
select_pins = PD0
run_current = 1
sense_resistor = 0.056

The UART address has to be a number, usually 0,1,2, or 3.

You can’t negate a number with the ! in front of it.

5

You have the ! in front of the uart_addressas EddyMI3D pointed out, instead it needs to be inverting the select_pins. The comments in the generic config state that, but they way they are written is a bit misleading. Here is an excerpt from my Voron 2.4 that’s running on a Mini 5+ fully loaded with 7 drivers, (modified) PT100 daughter card, etc.

[stepper_y]
## DRIVER4
step_pin: PC16
dir_pin: PD21
enable_pin: !PC28

[tmc2209 stepper_y]
uart_pin: PA1
tx_pin: PA0
select_pins: !PD0
uart_address: 0
interpolate: False      # for improved positional accuracy
run_current: 0.89       # 64% of LDO-42STH40-2004MAH(VRN) rated 2A peak current
sense_resistor: 0.056
2 Likes
6

That worked perfectly, thank you!

And, “misleading,” is a light way to put it. That documentation is WRONG wrong, since the examples all show the ! before the uart_address.

7

What documentation?

8

The commented instructions in generic-duet3-mini.cfg on line 15.

“# Uart addresses - 0:0 1:1 2:2 3:3 4:!0 5:!1 6:!2 | “!” is for inverted select pin”

I guess technically speaking, if you already know that you need to invert the select_pins parameter, you can figure out what they’re trying to say, but without that prior knowledge, I can’t think of any other way to interpret it than the way that I did at first.

I was coming at this with no UART experience whatsoever, and I imagine most people using this config template aren’t either.

9 
...
# Uart addresses - 0:0 1:1 2:2 3:3 4:!0 5:!1 6:!2 | "!" is for inverted select pin
                                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...