External TMC 2208 UART

ShaunCro

@veti I thought of that, but if a power failure were to occur, the drivers would lose their config and print resume would be an issue.

I came across this last night while trying to find info on ways to accomplish this.

https://www.instructables.com/id/SPI-to-4-x-UART-Bridge-MULTIUART/

But, it would probably cost more than buying 3 TMC2130 drivers.

A Former User

Maybe this is of interest, guy using an external MCU to configure his TMC2208 at power on, leaving the original controller to do the step/dir stuff. I guess you could go one step further and craft a specially formatted M117 message that the external MCU could pick up and configure accordingly to make it a litt less of a pain to change the config.

https://github.com/Sergey-77/Cetus3d_TMC2208/blob/master/3_steppers_version/Attiny85_firmware_v2.ino

ShaunCro

Thanks @bearer , will definitely check it out.

A Former User

Come to think of it, I did upload a thing that parses the json message for the M300 beeps, should be relatively simple to adapt to parse the json sent by M117 and pick out the stuff you want and send it on with software serial from the esp8266 as well.

https://forum.duet3d.com/post/99591

also has another link to a similar effort.

oliof

You may want to look at the SMuFF which uses the paneldue port and an esp to control the filament changer from another printer board.

ShaunCro

@oliof Ironically, one of my printers is an i3 mini

dc42

The standard firmware supports only one type of smart stepper driver per board. For the Duet WiFi/Ethernet this is the TMC2660. For the Duet Maestro it is the TMC2208/2224 which are the same chip in different packages. So on the Meastro you can add two UART-controlled TMC2224 or TMC2208 drivers. On the WiFi/Ethernet you can add TMC2660 drivers. You can also add "dumb" step/dir/enable drivers. This could include TMC2208 drivers but they wouldn't be UART-controlled.

ShaunCro

@dc42 thank you very much for the reply DC.

Looking at the pin header of the Duet 2, I only see 2 x 3.3v power supplies. (On the 50 pin connector) Can I wire more than one board to the pin, or is it advisable to rather maker use of the two available on the 50 pin interface and wire the 3rd to the LCD-CON?

dc42

Yes you can use a single 3.3V pin to power multiple devices.

ShaunCro

@dc42 Thanks DC, will post updates in case anyone is ever interested in doing the same.