Raspberry Pi 4

MrGreg wrote:

@ blazini36 ( and indeed tommylight & all)

Yes as you may have guessed, I'm also V interested in reviving / resurrecting Picnc to run on Pi3 and prob more likely long term Pi4.

Re your comments Re Picnc on the MK forum, Guessing you mean this one?
groups.google.com/forum/#!topic/machinekit/wDCXCINWqTM

It's rather confused, the OP seems to have quite different intentions than his initial post suggested.

I think the subject is worthy of further discussion, but on a thread of its own. I will do that if there is any apparent further interest in the matter.

Re PiDiCnc ( Just saying for historical reference)
It has its roots in Picnc. The author/co author/whatever.. of PiDiCnc "Viktan" was quite active in the RPIforum topic where Picnc was started ( initially Linuxcnc)
See ( starts here & there 40+ pages of it, A Very long read)
www.raspberrypi.org/forums/viewtopic.php...ad3805e465d425241e2d
And referencing his driver here.
forum.linuxcnc.org/27-driver-boards/2974...stem?start=50#115691

The Author of Picnc is "kinsamanka" BTW

I was quite attracted to PiDiCnc, Have kept an eye in it over the last couple of years, but also have reservations about, lack of price info, future prospects, source? general inactivity on his website, to mention a few.
The reported price point of 80Euro does seem attractive and good value for money. As to whether it works on a Pi4? Best you ask them first.

I think I had better buy another Pi4 to do some more dedicated testing.

Cheers
MrGreg

PiDiCnc Is using a simple Xc6slx9 with hostmot2. At this price I prefer buying a 7c81 by far. I’m using a XC6SLX16 with 96I/O in 3.3v for only 20€. For me a RPI is a cheap embedded solution so using a board which worth more than the RPI itself is too much, unless you need to control an industrial machine or something like that.
BTW I’m trying to install a realtime kernel on the last STM board, the STM32MP157. This could be the ultimate solution to have everything in one board (like the Zync or the De0 nano)

BeagleBrainz wrote:

Someone forget to make that link shareable ?

Yeah....lots of big ideas with MK, but not a lot of work done.

I saw a while ago that someone was working with the BBB, but bare metal, for cnc motion control. Tried look for the links, but to no avail.

Personally ATM I think the ol' X86 (_64) platform has the best long term viability. As long as the PC platform still has non-usb Ethernet running MESA Ethernet motion control is still a good long team option. Even more so for those that do commercial installations. Plus the fact I am unaware of the RPi being certified for industrial use.
Now what would be interesting is a BBB with similar specs to the RPi4 and still keeping the PRU subsystem.

Yeah I forgot to share it the link...

drive.google.com/open?id=1ih-1KqdshXeu-BHIEUqMd9f8SUqrkrQf
also open sourced this project just hoping someone would contribute some improvements, it is fully usable as is though.
github.com/ShadeTechnik/socfpga-developement-OSHW

And actually the work is done for the DE10-Nano on MKSOCFPGA, and it's quite good. Problem is that MK has a split CNC and hal stack and they all but abandoned the CNC stack. I keep thinking they should just push to get these things merged into LCNC, the big MK names have left the project and it just seems to be hanging on with only a couple of guys. I was not a fan of the BBB. I think the PRUs are great but the way the I/O must be sacrificed to just use the HDMI or eMMC becomes confusing and kind of kills it.

I recall seeing the PIDICNC stuff when it was first being mentioned on here. I honestly wasn't super interested because I have very little reason not to just buy Mesa stuff especially now that they have a couple of Rpi boards if I'm going to buy something. Without open-source firmware it just doesn't do anything for me, even though it looks like great hardware. I don't get overly concerned about the price of a Mesa eth card and don't really feel any need to seek out cheaper hardware. It amazes me that Mesa can do what it does for the cost...I've spent more on a single end mill than most of the mesa boards I've bought.

That said my interest in the PICnc-like board is not based on cost really. I build obscure machines on a whim running on LinuxCNC and my main goal would be to work up a I/O board that is specific to that exact machine but have the environment be exactly the same. So for this I would hope that the firmware and drivers would get sorted and some general I/O PCB were designed that the community was fond enough of to keep working the code out for. Now if that firmware is easily configurable and modular I can take that same micro, plop it on whatever PCB I come up with for whatever machine I'm putzing around with and that's that.

I can do exactly that with MKSOCFPGA right now as it runs hostmot2 and that is perfect. The problem is Machinekit itself and since soc-fpga's are a bit too complicated for me to implement myself, I'm reliant on something like the DE10-nano or whatever dev board and it's lifecycle and limitations and whether MK has developed for it. With a board that runs a PIC or ARM microcontroller over spi, it can be controlled by any number of ARM boards or an Odroid-H2 that I'm so fond of if I need a bit more CPU for whatever else the machine is doing. In general I have no concerns about running anything on an rpi4, it is finally capable enough to do quite a bit but at the same time.....it's not a requirement to use the rpi, just something with a capable spi interface.

I did come across this:
easyeda.com/MX_Master/lcnc_bb

Which looks like a fully designed schematic of an overkill STM32 cortex M4 board. I messaged the author about if he's done anything with firmware or anything with it but I haven't heard back. Other than the ethernet interface rather than spi it looks pretty good. I don't have an issue with ethernet, for something like this I just prefer the abillity to plug the pi or whatever directly into a header and since SPI is on the GPIO header it's just a better package.

I’m actually testing the port of the Hostmot2 firmware for an Artix 7 with XADC (analog for a 3D printer)
github.com/sleepybishop/artix_hostmot2
I’m using this cheap board :
fr.aliexpress.com/i/1000006630084.html

This was my solution:
A cape that fits onto the BBB
Two daughter boards that connect via small ribbon cables.
I was able to bring out 34 lines fro I\O and the 25th to enable the outputs whilst keeping HDMI
I ran this until I switched to Linuxcnc with an ealry wheezy image that was well before things were split
This is my github with more info github.com/ozzyrob/

Nice board ! I’ve a couple of board like this to interface a FPGA with the RPI.
I’m using the FST16211 for I/O 5v (24bit gate) but it’s hard to solder by hand (unfortunately I don’t have a PNP machine)
If someone knows a easier chip to solder (different package) ....

A big chisel chip, as hot as you can get it, and lots of liquid flux is the answer.

Place the chip
Flow the liquid flux on all sides
Load up the tip with solder
Quickly run the iron all sides of the chip, just at the end of pins
Let the chip cool
Flow more liquid flux
Where there any bridges touch the edge of the pins, capillary action will draw the solder onto the tip.
And clean the flux off.

I used to do this day in and day out in a repair shop, chips down to .5mm pitch.

gtt38 wrote:

I’m actually testing the port of the Hostmot2 firmware for an Artix 7 with XADC (analog for a 3D printer)
github.com/sleepybishop/artix_hostmot2
I’m using this cheap board :
fr.aliexpress.com/i/1000006630084.html

How is that going? I might be interested in doing something like this as well but eventually sticking the fpga directly on the PCB. It's just kind of difficult to figure out how to get started with the whole firmware thing. All I've done so far is write some bitfiles for MKSOCFPGA and spun them through the docker build that they have setup to get some firmware spit out.

Are we at a stable point to be able to run on the Pi4 "4 gb" with a 7i77 and analog servos "PWM" ? If so, does anyone have a link or an image available?

blazini36 wrote:

How is that going? I might be interested in doing something like this as well but eventually sticking the fpga directly on the PCB. It's just kind of difficult to figure out how to get started with the whole firmware thing. All I've done so far is write some bitfiles for MKSOCFPGA and spun them through the docker build that they have setup to get some firmware spit out.

Sticking on which pcb ? create a RPI hat you mean ? not really good, i already tried with an XC6SLX9 and the pb is the heat. I prefer have a good fan under the RPI4 than an FPGA hat. SLX16 and Artix are BGA package so its difficult to solder by hand.
The Hostmot2 firmware SPI can be ported to every xillinx FPGA younger than XC6, like all XC7 familly including Zync. The port of Hostmot2 on Vivado by Joseph Calderon was only tested in SPI but could work in ETH and PCI (untested).
The pb is that FPGA are expensive. an XC6 is enough for all linuxcnc applications.

The limitation is at 96 I/O maximum it could be very low for some specific applications, maybe we could find a way to reach 128 or 256 user I/O using some new FPGA like ARTIX 35K or 100K, or creating 2x HM2 firmware in a single FPGA if there is enough cells. it could be very easy and with a double SPI communication (SPI0 and SPI1) 2x96 = 192 I/O