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Does anyone in or near Germany have a spare STM32 Bluepill PCB available?


Uwe Glässner
 

Hi All,
I would love to upgrade an old Vixen GP mount with onstep using the STM32 Bluepill based board. I was wondering if anyone in or near Germany has an additional PCB that he would part with? Ordering them at JLCPCB would work as well, but seems to have a minimum order of five, so I thought I ask here first if anyone has unused PCBs lying around? ;-)
Thanks a lot in advance!
Best
- Uwe


Khalid Baheyeldin
 

George Cushing sells complete STM32 Blue Pill kits, and for an additional fee, he can solder and test it for you as well.

Here is his web site and email

https://www.stmbluepillkits.com/2020/07/stm32-kits-are-again-available.html


Jochen.Siegfried@t-online.de
 

Uwe,

 

if you  want to order from Geoge, I would propably order one too, so we can share the shipping costs ...

I would opt for a ready soldered one ....

 

 

Just let me know ...

Regads

Ferris




Uwe Glässner
 

Thanks Khalid,

I have just dropped George a mail to ask if he still has complete kits available. I just learned about the recent issues with the 64k bluepill boards so would like to avoid the risk of not getting this sourced. I also read that you are currently testing a replacement board for the bluepill: Will that require changes to the STM32 PCB? If George doesn't have any kits (or shipping costs to Germany are too high) I might still want to order a PCB through JLCPCB, but if larger changes are required that might not be a smart idea now ... ;-)

And one last question: I tried to get up to speed with the stepper-motor and stepper-driver terminology in the last days: Am I right that on-the-fly mode switching using the TMC2209 driver is not possible on the MKS Gen L, the FYSETC S6 and also the Wemos R32 / CNC boards because all of them use fixed jumpered microstep settings? Since I just received two nice TMC2209 drivers from Watterott that limits my options then to the STM32 or the Mini/MaxPCB if I want to use this feature, correct?

Thanks a lot for your help in this group!

Cheers
- Uwe


Khalid Baheyeldin
 

On Wed, Oct 21, 2020 at 11:43 AM, Uwe Glässner wrote:
I also read that you are currently testing a replacement board for the bluepill: Will that require changes to the STM32 PCB?
The issue is that the STM32F103 Blue Pills are sold as 64K flash size, but until recently, they were practically all 128K.
Now, there is a significant amount of stock with only 64K which cannot run OnStep.

So there is no way to be sure that a Blue Pill is 128K before buying it.

On the other hand, we are testing a replacement module that is pin compatible (works in the Blue Pill PCB), but has a few advantages over the Blue Pill. This should be announced in the coming week or two.

So, if you buy a Blue Pill kit, it will work with this new module too.

And one last question: I tried to get up to speed with the stepper-motor and stepper-driver terminology in the last days: Am I right that on-the-fly mode switching using the TMC2209 driver is not possible on the MKS Gen L, the FYSETC S6 and also the Wemos R32 / CNC boards because all of them use fixed jumpered microstep settings?
OnStep supports mode switching with regular drivers (LV8729, S109), as well as SPI drivers (TMC2130, TMC5160) on purpose built OnStep boards (MaxPCB, MiniPCB, Blue Pill PCB).

On the 3D printer boards, only the SPI drivers (TMC2130, TMC5160) support mode switching.

Since I just received two nice TMC2209 drivers from Watterott that limits my options then to the STM32 or the Mini/MaxPCB if I want to use this feature, correct?
The TMC2209 is kind of odd. People do get it working, and it provides high current and silent operation, but OnStep does not have the UART support required for full operation. But if I look at the code, I see that it supports 64,32,16,or 8 microsteps, and supports MICROSTEPS_GOTO as well. So maybe the limitation is that it cannot use 4 and 128 microsteps? Also not sure if this mode switching will work on 3D printer boards or not.


Uwe Glässner
 

Thanks again Khalid,

having never worked with steppers before this is really a steep learning curve ;-). Good to know, that the STM32 board might get an alternative board option. It really has an attractive feature set. 

Regarding the mode switching on the TCM2209: As far as I understand it (being a newbie ;-), pins M0, M1 and M2 of the drivers are connected to CPU IOs in the custom boards, so the step/dir microstepping modes can be switched on the fly using the parameters you mention. On the 3D printer boards (and also the CNC board) it seems that you have to fix the microstepping mode using the jumpers below the driver so no on-the-fly switching in on-step (unless you use SPI capable drivers like the TMC2130 or 5160 that allow mode changing though SPI).


Khalid Baheyeldin
 

On Wed, Oct 21, 2020 at 12:30 PM, Uwe Glässner wrote:
Regarding the mode switching on the TCM2209: As far as I understand it (being a newbie ;-), pins M0, M1 and M2 of the drivers are connected to CPU IOs in the custom boards, so the step/dir microstepping modes can be switched on the fly using the parameters you mention.
Correct.

On the 3D printer boards (and also the CNC board) it seems that you have to fix the microstepping mode using the jumpers below the driver so no on-the-fly switching in on-step (unless you use SPI capable drivers like the TMC2130 or 5160 that allow mode changing though SPI).
Correct.

The designers of 3D printing board used jumpers to select a fixed microstep value, without the software (Marlin, ..etc) having control over it. Then when SPI drivers (made by TMC) came around, they wired the board for that protocol, with shared wires for all drivers. That means when a 3D printer board is used for OnStep, it cannot do mode switching on the fly.

But realistically, the S6 is very fast, and therefore even with the LV8729, I can get ~ 4 degrees per second, when using PULSE mode, with 28,800 steps per degree.

See this video

https://www.youtube.com/watch?v=1vsFJ63CUwI

So the only practical limitation would be with the MKS Gen-L and regular (non-SPI) drivers.


Uwe Glässner
 

Thanks for the confirmation! There are so many different hardware options that it is easy to overlook constraints among them. Good to know that the S6 would also be an option.


Khalid Baheyeldin
 

On Wed, Oct 21, 2020 at 01:18 PM, Uwe Glässner wrote:
Good to know that the S6 would also be an option.
I took the effort to make OnStep work on the FYSETC S6 because it fills a needed niche.
It is already built, so no selecting components (confusing for many) or ordering them, or soldering (hard for many).
It also offers support for all OnStep features, because it has lots of pins, and built in heater/fan connections.
It is basically a faster MKS Gen-L, which has proven to be popular.

The Blue Pill board on the other hand requires some soldering skills. Ordering is not a problem anymore, because
George Cushing makes kits available. It has one focuser, which works for most people, but not all (those who
require a focuser on the guide scope for example), and no heaters (not an issue if you have separate heaters).

So yes, there are many choices, and that is why people come to ask questions.