MKS Robin Mini, VREF is generated in SW

[PSLLSP]

Board MKS Robin Mini has stepper drivers A4988 soldered on board but there are no trimmers to set VREF voltage for these drivers. VREF is generated with PWM by CPU. I cannot see any reference to VREF voltage in clipper configuration file generic-mks-robin-mini-v2.cfg. I assume that VREF will be just some random value, it could be too low or too high. Do I miss something?

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MKS Robin mini generates 3 voltages for VREF:

• pin PA6 - VREF for X and Y
• pin PA7 - VREF for Z
• pin PB0 - VREF for E (Extruder)

https://github.com/makerbase-mks/MKS-Robin-mini/tree/master/hardware

This is in Marlin configuration pins_MKS_ROBIN_MINI.h

// Motor current PWM pins
#define MOTOR_CURRENT_PWM_XY_PIN   PA6
#define MOTOR_CURRENT_PWM_Z_PIN    PA7
#define MOTOR_CURRENT_PWM_E_PIN    PB0
#define MOTOR_CURRENT_PWM_RANGE    1500 // (255 * (1000mA / 65535)) * 257 = 1000 is equal 1.6v Vref in turn equal 1Amp
#define DEFAULT_PWM_MOTOR_CURRENT  { 1030, 1030, 1030 } // 1.05Amp per driver, here is XY, Z and E. This values determined empirically.

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One more note/issue

Why README has instruction to rename firmware to Robin_nano35.bin? It is board Robin mini...

Rename as Robin_nano35.bin
Copy Robin_nano35.bin klipper firmware to TF card and insert board

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One more note to README. Please update it with information if touch screen (2.4", connected with flat ribbon cable to MKS Robin Mini) will work with Klipper. I assume that it will not work. Please, update README with this important information...

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Try it

[output_pin xy_pin] pin: PA6 pwm: True cycle_time: 0.001 hardware_pwm: True value:0.5

[output_pin z_pin] pin: PA7 pwm: True cycle_time: 0.001 hardware_pwm: True value:0.7

[output_pin E_pin] pin: PB0 pwm: True cycle_time: 0.001 hardware_pwm: True value:0.8