What’s the stance on RRF on none Duet boards?

sinned6915

@jay_s_uk out of curiosity, what is the relative cost between say :

STM based board + SBC + display solution
vs.
Duet2 clone + display solution

so we can compare it to OEM?

zapta

@jay_s_uk said in What’s the stance on RRF on none Duet boards?:

the 1768/69 don't have it

Got this week two SKR 1.4 'turbo' for an upcoming Voron 2 build but now that you mentioned I checked and indeed they use a measly LPC1769, but still better than the 8 bit Prusa MK3.

The Voron uses Klipper so the heavy lifting computation is done on the SBC so so I expect good performance.

Do the Chineese manufactures upgrading now to STM32F4? E.g. the SKR pro and the FLY E3? Do they use STMicroelectronics chips or do they have local clones?

jay_s_uk

@sinned6915

STM

Wifi

The STM doesn't need an SBC to function.
The cheapest board is probably the SKR-RRF-E3 which can be had for around £30. It has built in 2209's and can't support an SBC. You can then use any one of the screens available, i.e. paneldue, fly scree, BTT TFT or 12864. So you could have a complete setup for around £40. It does however only have 4 drivers (there is an addon board that adds another 2 drivers which adds another £10 to the cost) but there are other boards that have 5 or more drivers (Fly-E3-Pro has 5 onboard, SKR 2 has 5 replaceable, Fly-CDYv2/SKR Pro have 6 replaceable, Fly-407ZG has 9 replaceable and SKR GTR + M5 has 11 replaceable).

For some of the boards an additional wifi adapter is needed which is around another £8.

We also don't currently offer any ethernet based boards, so if ethernet was required then an SBC setup would be needed.

SBC

To use an SBC, the boards require an additional set of adapters (you can roll your own), which are around £8-10.

Clones

The duet 2 wifi can be purchased for around £45 but you don't know what you're getting with those.

jay_s_uk

@zapta

I know fly/mellow uses original unused STM32F4 processors. Prices have also started to raise a lot recently.

We believe BTT is using secondhand STM32F4 processors (hence the slightly cheaper prices) but we can't substantiate that either way.

zapta

@jay_s_uk said in What’s the stance on RRF on none Duet boards?:

SKR 2 has 5 replaceable...

I am not sure what I think about the replaceable vs soldered. On one hand, the replaceable are easier to replace when something goes wrong but on the other hand the connector is another thing that can go wrong and overall it looks as a 'ghetto' design.

zapta

@jay_s_uk, the new rave in Chinese boards is the Fysetc Spider. STM32F446 with 8 replaceable TMC2209 for $60 shipped. It has 5V and 12V buck converters for external devices and marlin and klipper support, and got design input from the Voron dev team with the goal to replace the two SKRs. I don't see anything about a wifi dongle.

https://wiki.fysetc.com/Spider/

What's the process of getting RRF support for a new board like this? Is it typically done by the vendor or by the community?

EDIT: The wiki page says this: "As RRF firmware requires more than 512KB of Flash space, the Spider equipped with 446 cannot meet its requirements. So Spider has another version dedicated to running RRF firmware, which uses STM32F407VGT6 MCU."

jay_s_uk

@zapta that board won't get added in its current form.
They've chosen an MCU with only 512kb of flash and the firmware as it stands is already bigger than that for a wifi build
They are releasing a 407 version I believe. Lets just hope they choose the right processor

zapta

@jay_s_uk said in What’s the stance on RRF on none Duet boards?:

Lets just hope they choose the right processor

Just posted an EDIT. The RRF processor is STM32F407VGT6

jay_s_uk

@zapta thats the same processor used on the Fly-E3, E3-Pro, SKR-RRF-E3 and SKR 2.
The next challenge is getting the information for it or even getting a board for testing.

zapta

@jay_s_uk, when I click on Compatible Boards at https://www.reprapfirmware.org/ it shows only Duet3d boards.

Have you tried discussing with reprapfirmware.org owners (Duet3d?) having a more vendor neutral page that lists all boards?

The boundary between RRF and Duet3d is confusing to me.

jay_s_uk

@zapta
Never even thought about that page.
I would have to approach duet3d about it.

dc42

@jay_s_uk said in What’s the stance on RRF on none Duet boards?:

@zapta that board won't get added in its current form.
They've chosen an MCU with only 512kb of flash and the firmware as it stands is already bigger than that for a wifi build

Bigger than 512kb? Sounds odd to me. Duet2CombinedFirmware for the Duet WiFi and Ethernet is currently 500kb and has the code for both WiFi and Ethernet included. It's only the Duet 3 and 3 Mini builds with CAN support that are bigger than 512kb.

jay_s_uk

@dc42 Yep, this is from Andy

The latest development WiFi build (which by default loads at address 0x08008000 (so we allow 32K for the bootloader) already uses flash memory up to 0x0808fecc which is a total of 543Kb of flash which means a total size (with the bootloader) of 575kBytes.

dc42

@jay_s_uk I see, it's because 32kb is already taken up by the bootloader.

jay_s_uk

@dc42 yep

I also don't know how much the board.txt functionality and multiple board support takes up.
We also produce separate builds for wifi and SBC

gloomyandy

@dc42 There is a further 32K that is used for NVM emulation to hold the stack/registers after a reset. This is rather wasteful but on the chips we currently support not really an issue.

Some other things are also a little different in that we have additional code to support any mixture of TMC2208/2209/5160 drivers. A software based UART (for TMC drivers) and software SPI. I'm also pretty sure that our CoreN2G has rahter more in it than strictly needed.