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Question BTT Octopuis Pro with H723

ChrisA

Well-known member
I'm looking at ordering the "Pro" version of the Octopus. There is a choice of three different STM32 chips. The H723 seems to be the fastest of them but the BTT Github documentation only covers the the F4 versions of the chip.

When I compile Klipper, Menuconfig asks for things like the "reference clock" and bootloader offset and other questions. The Docs only cover this for the F4x chips. Is there docs for the H723 someplace?

Why the "Pro"? I want to try to see how fast I can spin the A/B stepper motors and for that, I'll need more than 24 volts. Yes, I know it's pointless.
 
Well, after reading your post I decided to go to BTT github and search for the information you are looking for and well, nothing. This seems like a MASSIVE oversight by them.

But I don't seem to be able to find the H723 for sale anywhere. I am wondering if it was only released for a shot time until a flaw was found?
 
Well, after reading your post I decided to go to BTT github and search for the information you are looking for and well, nothing. This seems like a MASSIVE oversight by them.

But I don't seem to be able to find the H723 for sale anywhere. I am wondering if it was only released for a shot time until a flaw was found?
It is certainly offered for sale. It is the default Octopus Pro version on the BTT web store. It is the only version 1.1 offered The F4 Pros are V1.0
BTT sent me an email this morning saying they shipped one to me

The other resellers all seem to cut and paste the same web page from some time ago. I don't think anyone in China proofread their web pages, lots of contradictory or missing information

I wanted the new chip because of course "faster is better" but I also want to try some software ideas and the high clock provides lots of headroom. One idea is that I think those optical sensors in mice could be used in 3D printers.
 
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Who doesn't like more speed? I certainly would like to try this board out as well but without proper documentation I fear it will be a struggle. Did BTT send you the flash recommendations?

Also take note of this bit of information.
1706618825917.png
 
For Klipper it looks like this to me

[*] Enable extra low-level configuration options
Micro-controller Architecture = STMicroelectronics STM32
Processor model = STM32H723
Clock Reference = 25 MHz crystal
Bootloader offset = 128 kib bootloader
Communication interface = USB to CAN Bus bridge ( USB on PA11/PA12)
CAN Bus Interface ( Can bus ( PD0/PD1))
CAN bus speed = 1000000
 
Good news is that MCU speed does not matter that much with Klipper. Pick whichever Pro you can get. Or whichever is safer and does not start heaters in DFU mode.
 
Who doesn't like more speed? I certainly would like to try this board out as well but without proper documentation I fear it will be a struggle. Did BTT send you the flash recommendations?

Also take note of this bit of information.
View attachment 4070

EDIT (2/11/24): I connected a new out of the box BTT Octpus Pro V1. (H723) to power. The Raspberry Pi is not connected. All heater pins were at zero volts. That is HE0, HE1, HE2 and HE3. They are all off. These are separate from the bed heater output. HEx are for hot ends, I think. The date of manufacture of this board is Jan 15, 2024.

Older version if the H723 did have a problem the two of the four heaters would come up in the "on" state and remain on until Klipper booted and turned them off.
END EDIT

That notice has been around for a while. I read another where BTT updated the board to use different MCU pins for the heaters. The new board is in the mail and I have a tracking number. I will be able to try it out LONG before I have a working printer. The very worst case is that I have to simply not use HE0 and HE2.

As for why I want a faster clock when I know the bottleneck to faster printing is the extruder and cooling, I want to try to software development experiments with Klipper. For one, I have some ideas about where and how the optical sensor from a mouse could be used in a printer. Also, I want to try closed-loop control of the A and B motors with the loop closed in the MCU. (don't wait up on any of this, it might not even work)
 
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That notice has been around for a while. I read another where BTT updated the board to use different MCU pins for the heaters. The new board is in the mail and I have a tracking number. I will be able to try it out LONG before I have a working printer. The very worst case is that I have to simply not use HE0 and HE2.

As for why I want a faster clock when I know the bottleneck to faster printing is the extruder and cooling, I want to try to software development experiments with Klipper. For one, I have some ideas about where and how the optical sensor from a mouse could be used in a printer. Also, I want to try closed-loop control of the A and B motors with the loop closed in the MCU. (don't wait up on any of this, it might not even work)
Did you test your BTT H723 Octopus pro yet?
 
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