Unknown command: "M42"

Sasha · February 1, 2021, 8:55am

Hi to community, my first post (Lowrider is under construction). So far I’m satisfied with progress of making Low rider 2, board (Makeboard mini v2.1.1 - treated as Ramps) and steppers are savaged from delta 3d printer. V13DP_Ramps_MK8-2.0.7.2 fw is installed with minor adjustment mostly display settings - so far so good everything works.
Now, my goal is to control pin 9 to control external relay, this pin is used by default as fan pin.
When I send command from Repetier-Host: M42 P9 S1
it returns -> echo:Unknown command: “M42”. Same for “M2” only - to turn on led on pin 13.
Any ideas,
Thank you

dart1280 · February 1, 2021, 11:03am

Marlin command to control the fan is M106 to switch it on full power and M107 to switch it off.

M2 ends the program.

The pin number used is set in the configuration files, while I am not familiar with the firmware you are using, or the board, I would have thought the fan pin number would already be set up correctly.

Sasha · February 1, 2021, 11:22am

@Mike Thank you.
Yes I was able to control it via M106 & M107, but was wondering why M42 is refused by Marlin. The board has several unused pins and I have some future plans to use it to control vacuum etc…

dart1280 · February 1, 2021, 11:31am

In order to support a wide range of machine types and disciplines there are many versions of Marlin. M42 is not supported in the version you have.
You can setup Marlin to control more than one fan and control them individually using the P option (M106 P2 S128 to turn on fan 2 at half power), then it is just a question of finding the relevant part of the configuration to enable more fans and assign a pin to them. Just be aware of the max current rating of the uP output pin and the current drawn by whatever you connect to it. The Fan has a MosFET driver, the other outputs probably won’t have.

Sasha · February 1, 2021, 11:47am

Mike, Thank you.
Initially my opinion was that my version doesn’t support M42, but under:
Marlin\src\gcode\control
there is M2.cpp file
That confuse me

jeffeb3 · February 1, 2021, 12:49pm

This is for a 3D printer. Did you mean V1CNC?

M42 has worked in the past. I didn’t know it was disabled. Here is the doc for it:

jeffeb3 · February 1, 2021, 12:54pm

This note makes it look like you need to enable DIRECT_PIN_CONTROL:

github.com

MarlinFirmware/Marlin/blob/2.0.x/Marlin/src/gcode/gcode.h#L112


*        OR, with 'C' get the current filename.
* M28  - Start SD write: "M28 /path/file.gco". (Requires SDSUPPORT)
* M29  - Stop SD write. (Requires SDSUPPORT)
* M30  - Delete file from SD: "M30 /path/file.gco"
* M31  - Report time since last M109 or SD card start to serial.
* M32  - Select file and start SD print: "M32 [S<bytepos>] !/path/file.gco#". (Requires SDSUPPORT)
*        Use P to run other files as sub-programs: "M32 P !filename#"
*        The '#' is necessary when calling from within sd files, as it stops buffer prereading
* M33  - Get the longname version of a path. (Requires LONG_FILENAME_HOST_SUPPORT)
* M34  - Set SD Card sorting options. (Requires SDCARD_SORT_ALPHA)
* M42  - Change pin status via gcode: M42 P<pin> S<value>. LED pin assumed if P is omitted. (Requires DIRECT_PIN_CONTROL)
* M43  - Display pin status, watch pins for changes, watch endstops & toggle LED, Z servo probe test, toggle pins
* M48  - Measure Z Probe repeatability: M48 P<points> X<pos> Y<pos> V<level> E<engage> L<legs> S<chizoid>. (Requires Z_MIN_PROBE_REPEATABILITY_TEST)
* M73  - Set the progress percentage. (Requires LCD_SET_PROGRESS_MANUALLY)
* M75  - Start the print job timer.
* M76  - Pause the print job timer.
* M77  - Stop the print job timer.
* M78  - Show statistical information about the print jobs. (Requires PRINTCOUNTER)
* M80  - Turn on Power Supply. (Requires PSU_CONTROL)
* M81  - Turn off Power Supply. (Requires PSU_CONTROL)
* M82  - Set E codes absolute (default).

Sasha · February 1, 2021, 2:54pm

Thank you @jeffeb3,
yup as you noted wrong type of marlin. Now downloading V1CNC and will refer buck.
Once more thank you!

Sasha · February 1, 2021, 5:23pm

Correct version of fw was installed-V1CNC and enabling DIRECT_PIN_CONTROL in gcode.h now M42 works.
Guys, thank you for the contibutions!