Remora - Rpi Software Stepping Using External Microcontroller via SPI

I have not tried on a RPI3 only 4.
did you enable SPI?
www.raspberrypi-spy.co.uk/2014/08/enabli...on-the-raspberry-pi/

I would setup serial and double and triple check your wiring.

Also going to try and play with the new PWM stuff and see how it works.

They should have a pinout layout just like you'll find for the BT SKR v1.4 and then you just need to see that the signal/pin numbers are the same as the official BT SKR v1.4 and if they are it should work. Sames goes for the v1.3 although I'm not sure that's been tested. The MKS Sbase v1.3 is the only "v1.3" I've verified works.

If the pin numbers are different then it's still possible it'd work but you might need to build the firmware from source and adjust pin numbers accordingly.

Yes spi is enabled in raspi-config, and rebooted afterwards

the wiring ohms out ok from bottom of rpi to bottom of skr ( thru cable)

Setting up serial is not simple on V1.3 (not like 1.4)
but i have a hint
Big Tree has website /repo at bit.ly/3gBodKq
and they talk of wiring up a serial port on page 11or12

thanks tomp

On SKR V1.3, the TFT connector is rotated 180 deg from the v1.4
so I will try after making the dupont connector\

tomp

I got the serial comms working on the SKR V1.3 ( no BTT laogo)
I had gtkterm monitoring /dev/ttyAMA0 at 115200
from what i see m a lot is working and i have a fatal? error on
a non-existant temperature sensor
so i will try a very stripped down config
(I am happy that the comms work)

the comms are 3 pins on SKR V1.3 'TFT' male hear
to 3 pins on RPi3B+
the TFT header, if we let left pin be #1 ( oriented with pololu sockets at 'top')
and the SKR situated to left of RPI
and RPI oriented with usb at (top), and pin 2 of its 40pin hdr at bot left.
( btw the v1.3 tft cnxr is 180 degree rotated from the V1.4 )

then 3 wire jumpers can do this 'cable'
now some file changes to get serial port set up

sudo edit confgi.txt, adding to end of file save and close

and then sudo edit cmdline.txt
and remove the 2nd chunk ' save and exit

then reboot
open gtkterm
config to /dev/ttyAMA0 at 115200

let this window remoin opne

open linuxcnc in another ttermial
run a remora cfg

look back at gtkterm to see lotsa stuff

press the SKRv1.3 reset
to get the messages from the beginning
and capture to a file for further investigation

easy peasy
;-/
tomp

I would just redo the normal setup of Remora and then use the basic setup which is the remora_xyz LinuxCNC sample config.
1) git clone of Remora then git status to see it is main branch
2) cp firmware/firmwareBIN/LPC1768/firmware.bin to uSD
2a) cp firmeware/sampleconfig/skrv1.3/config.txt to uSD
look at the config and verify the pin numbers match your board
3) on rPi git clone Remora and git status to see main branch
4) cd Remora/LinuxCNC/Components/Remora, run sudo halcompile --install ./remora.c
5) cd ~/Remora/LinuxCNC/configSamples, cp -a remora-xyz ~/linuxcnc/configs/
6) power up controller with the uSD installed, start LinuxCNC and select remora-xyz from myconfigurations, click the power button and see the e-stop enable then click it. Might have to hit the power button a second time to enable the e-stop.
7) move a motor and verify direction and distance is as expected.