TMC2660 on stepper channels 10 and 11

CVMichael · 11 Mar 2019, 23:14

I already have the Duex5 connected to the Duet WiFi, but I want to add another 2 stepper motors
Does Duet sell a board that plugs into stepper channels 10 and 11 ? (I searched online and did not see any)

I was thinking to make my own PCB board with 2 x TMC2660 stepper drivers, but I ran into a problem / question:
Does SPI (SDO, SDI, SCK, and CSN) need to be connected to main board (on the Duet WiFi) in order to configure the microstepping, interpolation, motor current, or other settings? and if "Yes", then what pins?

dc42 · 12 Mar 2019, 16:55

Yes, to drive TMC2660s from the driver 10/11 outputs, you would need to connect the following pins:

ENN - connect to ENN on the expansion bus
CSN - connect to the corresponding ENABLE pin on CONN_LCD
SDI, SDO, SCK - connect to SPI1_MOSI, SPI1_MISO and SPI_SCK on the expansion bus

You would also need to recompile the firmware, changing MaxSmart drivers in Pins_DuetNG.h from 10 to 12, and assigning 12 to numSmartDrivers in Platform.cpp instead of 10.

CVMichael · 17 Mar 2019, 17:43

Sorry, but I am still trying to figure out the connections.

"ENN - connect to ENN on the expansion bus" - what pins? I only see "En 10" and "En 11" on the CONN_LCD, but I don't see any 10, 11 on the expansion bus.

"CSN - connect to the corresponding ENABLE pin on CONN_LCD" - is this the "En 10" and "En 11" ?

I am confused between ENN and CSN....

What is the "Stop 10" and "Stop 11" ? pins 3 & 4 on the CONN_LCD, is this for the CSN ?

"SDI, SDO, SCK - connect to SPI1_MOSI, SPI1_MISO and SPI_SCK on the expansion bus" - I already have a Duex5, and I don't see any pins for the SPI1 (I see quite a few for SPI0 though). Does this mean that I will have to sodder wires in the back of the Duet PCB to bring the SPI1 to my motor driver PCB?

Since I want to make a PCB for both channels 10 & 11, I assume SPI is connected in parallel, but CSN is separate?

I created a schematic, if you have some time to take a look at it, and let me know if you see any mistakes:
This is the driver hierarchy block:

and this is the main schematic / connections:

I made the schematic in DipTrace, if you want me to upload the DipTrace file, let me know.
Also, I am novice at electronics, so please forgive me if it does not look professional

I will also design the PCB once I know the schematic is correct. I can upload all the files if anyone else is interested to do this.

dc42 · 17 Mar 2019, 20:30

@cvmichael said in TMC2660 on stepper channels 10 and 11:

"ENN - connect to ENN on the expansion bus" - what pins? I only see "En 10" and "En 11" on the CONN_LCD, but I don't see any 10, 11 on the expansion bus.

I mean the expansion bus on the 50-pin connector. You will need to tap into that bus, e.g. by clamping a 3rd IDC socket on the 50-way ribbon cable. Or you could have a couple of 50-way connectors on your expansion board, then use a short ribbon cable to connect the Duet to your expansion board and another ribbon cable to connect the DueX to your expansion board.

"CSN - connect to the corresponding ENABLE pin on CONN_LCD" - is this the "En 10" and "En 11" ?

Yes.

What is the "Stop 10" and "Stop 11" ? pins 3 & 4 on the CONN_LCD, is this for the CSN ?

No, those are for endstop switches.

"SDI, SDO, SCK - connect to SPI1_MOSI, SPI1_MISO and SPI_SCK on the expansion bus" - I already have a Duex5, and I don't see any pins for the SPI1 (I see quite a few for SPI0 though). Does this mean that I will have to sodder wires in the back of the Duet PCB to bring the SPI1 to my motor driver PCB?

See my comments on ENN above.

Since I want to make a PCB for both channels 10 & 11, I assume SPI is connected in parallel, but CSN is separate?

All the control inputs are in parallel except for CSN, STEP and DIR.

I created a schematic, if you have some time to take a look at it, and let me know if you see any mistakes:

The sense resistors should be 0R05 not 0R1
VCC_IO should be +3.3V not +5V.
There should be a 100uF electrolytic cap on the +24V supply close to each driver
We have 1nF capacitors for each output to ground to help with EMI and immunity to inductive spikes

See the Duet schematic at https://github.com/T3P3/Duet/blob/master/Duet2/Duet2v1.04/DuetWifiv1.04a_Schematic.pdf for how we connect the TMC2660s. The resistors shown as 0R051 are 0R050 in recent production.