Arduino DUE + RADDS + TMC2208 UART

Hi all...im new here and I bought a RADDS Shield for arduino DUE and a couple of tmc2208 from waterrot...my question is how can I use the tmc2208 drivers in uart mode...i will use on X Y Z axis and for 2 extruder I will use lv8729 or a4988 drivers..
I'm searching on Google few days now to try to find an answer but I didn't find anything

the general idea is covered here [www.instructables.com]

the actual pins will have to be changed for the RADDS

radds is not very popular due to its lack of availability and closed source nature.

Ok...so where do i need to change the pins...in marlin 2.0, under pins_RADDS.h?
I will use the available pins from max endstop,or from lcd connector that is on radds...because i don't planing to use lcd...or if i will use lcd...i have the aux1 pins available as well..that aux1 pins on radds is for adding the extra extruders with the expansion board v2 or v3
so my question is that i have to activate serial in marlin...or only need to assign the tx and rx pin for each axis where i will use tmc2208?

Edited 1 time(s). Last edit at 10/12/2018 06:14AM by weed2all.

This is the pins_RADDS.h
Where should I put the pins for tx and rx?
Should I create a new line for each axis with
#define X_TX_PIN ...
#define X_RX_PIN ...
Where ... Is the pin number that I want to use?

Edited 1 time(s). Last edit at 10/12/2018 06:15AM by weed2all.

weed2all , have you succeeded to make it work?
With soft_uart library maybe, to configure DUE with additional UARTs ?

I can't help with the RADDS board but the current software serial driver code for talking to the TMC2208's can operate with just a single pin (half duplex mode) rather than seperate TxD and RxD pins, so that means you don't need the TxD pin.

Once you find out which pins you want to use, just specify the same pin for TxD and RxD for each TMC2208.

You'll need a 1k or so pull-up resistor from each RxD pin to +5V.

Edited 1 time(s). Last edit at 04/25/2019 04:23PM by Pippy.

Hi Pippy, I must immediately say sorry if I write some stupidity or non sense but my programming knowledge is near to zero.
Thank you for sharing your knowledge, I would be very grateful if you could answer a few questions.
FIRST QUESTION
I read elsewhere ( [github.com] look at comment of MagoKimbra) that the problem with activating software serial uart on arduino due with tmc2208 is the old library for TMC 2208, and that the modification you did to the serial (that is very useful because it reduces to half the pins used) is an improvement but not strictly necessary.
The library of tmc2208 has a few lines where it says:

#define SW_CAPABLE_PLATFORM defined(__AVR__) || defined(TARGET_LPC1768)
#include < Stream.h>
#if SW_CAPABLE_PLATFORM
	#include < SoftwareSerial.h>

and if I understand correctly that means that software serial uart library will be included only on AVR and LPC1768 platforms and not on arduino Due. Am I right?
1) How did you get your system working without modifying also this tmc2208 library?

SECOND QUESTION
I read your other post [reprap.org] where you say you added a section in some file of marlin 2.0 with the defines of the various rx a tx pins. Where did you put such modification? In the pins_(one_motherboard).h file of your motherboard?

Thank you so much. This is all to try to get UART on TMC 2208 working on a RuRAMPS1.1 that is a similar to RADDS Shield of ARDUINO DUE etc.

Edited 6 time(s). Last edit at 05/26/2019 11:55AM by nixa.

Hi...so what is the current state of this?