Revolt A2
Revolt is a dual 48 V compatible stepper motor driver add-on board. It is based on TMC2160.
Contents
Hardware connections
The Revolt add-on baord is designed to stack on top of the Recore A7 board. There are two dual row connectors on the Revolt board, but only one on Recore A7. The enable/disable for the TMC2160 drivers are connected to the +24V from the bottom board, so the drivers are enabled when . It is enabled by default. There is also no diag output from the drivers. Those are broken out on the two other rows and can be connected to pins on the MCU header or DBG header if sensorless homing is required.
Klipper config
This config is using stepper x and y as the high voltage drivers, typical of a core-xy printer setup for speed. This gives the option of having 4 Z-drives and two extruders, 8 steppers in total.
This section sets up the two drivers (X = S6 and Y = S7)
[tmc5160 stepper_x] run_current: 0.6 hold_current: 0.2 sense_resistor: 0.05 cs_pin: ar100:PD0 spi_software_sclk_pin: ar100:PD2 spi_software_mosi_pin: ar100:PD1 spi_software_miso_pin: ar100:PD3 chain_position: 2 chain_length: 2 stealthchop_threshold: 9999 [tmc5160 stepper_y] run_current: 0.6 hold_current: 0.2 sense_resistor: 0.05 cs_pin: ar100:PD0 chain_position: 1 chain_length: 2 stealthchop_threshold: 9999
To route step and dir signals to the same motors:
[stepper_x] step_pin: ar100:PL10 dir_pin: ar100:PE14 [stepper_y] step_pin: ar100:PL11 dir_pin: !ar100:PE15
Recompiling Klipper
Note
If you use Rebuild v1.0.0-RC0 or later, a recompilation is not necessary.
Klipper needs to be recompiled to add software based SPI. Starting with Refactor v3.2.0-RC3
cd /home/debian/klipper nano src/Makefile <remove thermocouple.c sensor_adxl345.c and sensor_angle.c> make menuconfig <enable Support software based SPI "bit-banging"> make clean make mv out/ar100.bin /opt/firmware/
Tuning curves
The following oscilloscope capture shows the Revolt A1 running a NEMA 17 stepper at 30 V. The traces are A1 output (yellow) and gate for A1 (pink). The tuning looks good, very little ringing.
Errata
- Plus and minus silkscreen has changed places.
- The enable LED is lighting even though the 24 V input is not present.