# Possible to run SV04 steppers using UART instead of standalone?
**URL:** https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685
**Category:** Sovol SV04 IDEX
**Tags:** firmware, advice
**Created:** [September 7, 2025, 4:23pm UTC](https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685 "2025-09-07T16:23:02Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Rossosaurus](https://forum.sovol3d.com/u/Rossosaurus)
#### Post date: [September 7, 2025, 4:23pm UTC](https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685/1 "2025-09-07T16:23:02Z")
I’ve currently been tuning my SV04 and trying to get it running a bit faster than stock. Currently my biggest bottleneck is the Y axis having to move such a large bed around. Having to get underneath the printer every time to alter the current going to the motors is a bit of a hassle and was wondering if it is possible to switch over to using UART for the steppers instead of having them in standalone mode without making any modifications to the mainboard like you have to with the Creality 4.2.7 boards? Would also make it much easier when it comes to tuning if I upgrade to a longer NEMA17 on too. Cheers all
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### Author:  [@cardoc](https://forum.sovol3d.com/u/cardoc)
#### Post date: [September 7, 2025, 8:23pm UTC](https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685/2 "2025-09-07T20:23:08Z")
Are you running Marlin or Klipper?
AFAIK (I don’t have the board schematic) the SV04 mainboard would require a “wire” run from the microcontroller to the motor driver to enable UART. You could, however, put the Y motor on a different board and utilize the multi MCU feature of klipper. That eliminates the need to fully recreate the umbilical cables to interface with a new mainboard.
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### Author:  [@cardoc](https://forum.sovol3d.com/u/cardoc)
#### Post date: [September 7, 2025, 8:43pm UTC](https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685/3 "2025-09-07T20:43:42Z")
Update:
According to
>
The UART pins ARE connected. They don’t specify which 4 are on which pin and the sub address of the individual drivers (4 per UART channel)
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### Author:  [@Rossosaurus](https://forum.sovol3d.com/u/Rossosaurus)
#### Post date: [September 7, 2025, 9:15pm UTC](https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685/4 "2025-09-07T21:15:39Z")
> [@cardoc](#):
>
> The UART pins ARE connected. They don’t specify which 4 are on which pin and the sub address of th
Funnily enough I was looking at this earlier and completely missed the UART section 🤦♂️. I’m running Bjoern’s fork of Marlin for the SV04 with a few modifications for the dragonburners I’ve mounted. What would your recommendation be to find out which drivers are UART enabled and enable UART for them?
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### Author:  [@cardoc](https://forum.sovol3d.com/u/cardoc)
#### Post date: [September 7, 2025, 9:23pm UTC](https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685/5 "2025-09-07T21:23:59Z")
@Bjoern It looks to me like Bjoern’s firmware has UART current control enabled.
You should be able to set driver current with M906
> **[Stepper Motor Current](https://marlinfw.org/docs/gcode/M906.html)**
>
> Set stepper motor currents in milliamps units. Send M906 with no parameters to report all stepper motor currents.
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### Author:  [@Rossosaurus](https://forum.sovol3d.com/u/Rossosaurus)
#### Post date: [September 7, 2025, 9:29pm UTC](https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685/6 "2025-09-07T21:29:00Z")
I did wonder if this was the case or not but got very confused as it seems no Marlin config has the stepper drivers defined in the usual place in configuration.h. When the print I currently have running finishes in an hour or so I will give it a test and report back. Cheers
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### Author:  [@cardoc](https://forum.sovol3d.com/u/cardoc)
#### Post date: [September 7, 2025, 10:10pm UTC](https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685/7 "2025-09-07T22:10:07Z")
All the advanced functions are configuration\_adv.h
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### Author:  [@Rossosaurus](https://forum.sovol3d.com/u/Rossosaurus)
#### Post date: [September 7, 2025, 10:19pm UTC](https://forum.sovol3d.com/t/possible-to-run-sv04-steppers-using-uart-instead-of-standalone/8685/8 "2025-09-07T22:19:23Z")
Update:
Just tried sending an M906 command through pronterface and it returned with “unknown command” so I guess it must not be enabled. What I meant was that there doesn’t seem to be a single #DEFINE X\_STEPPER \ command for any of the axis or extruders within any of the marlin SV04 firmwares so I’m not sure what drivers marlin actually thinks is being used. I tried defining all axis and extruders as TMC2209’s but I then get an error that X\_HARDWARE\_SERIAL, etc. must be defined for that to be the case.