Can I make auto-square setup using two limit switches AND use a third limit switch for max travel for same axis??

[ambadran]

if it is possible to use 3 limit switch setup for X axis (where 2 are used for auto square and third is for max). How can I enable this in the settings?
I know I am supposed to define the X_LIMIT_PIN_MAX. Do I need to do anything else?

[terjeio]

You need a grblHAL driver and a board that supports max limit switches - not many do.
Since you auto square your machine you may consider enabling soft limits if the board does not support max switches.

[terjeio]

I have added definitions/handling for max switches for all axes to the ST32F7xx driver, seems to work ok for XYZ.
I am not going to wire up and test all other combinations - board developers should verify correct operation.

[ambadran]

So you are saying it might be a wiring error from my side?? Is there anything I can do to verify that?
Do you need me to share the new mappings I made?
(The default SKR3 mapping doesn't and can't support max limit switch in their default places due to the fact interrupt pins can't share same bit number)

[ambadran]

Also, I am under the impression they are supposed to show up in the $PINS and $LIM grbl command. Am I even correct? or do max limit switches just not show up there?

[dresco]

So you are saying it might be a wiring error from my side??

Terje was saying he's added support to the F7 driver. I'll need to take those changes and add them to the H7 driver before they're available for the SKR3.

Do you need me to share the new mappings I made?

Sure, then I can at least verify the code. Thanks..

[ambadran]

Ok, great! Thanks! I'll be waiting for the updated driver for the STM32H7xx.

I only added the following flags in my platformio.ini file in the btt_skr_30_h743_tmc2209 environment
-D X_AUTO_SQUARE=1
-D Y_GANGED=1
-D Y_GANGED_LIM_MAX=1

and here is the new mapping for the SKR board, I just remapped the RESET, FEED_HOLD, CYCLE_START to PA1, PA2, PA3 respectively, remapped all the limit switches to the expr1 port

#define BOARD_NAME "BTT SKR-3"
#define BOARD_URL "https://github.com/bigtreetech/SKR-3"

#define SERIAL_PORT 1 // TFT header, GPIOA: TX = 9, RX = 10
#define SERIAL1_PORT 32 // ESP-32, GPIOD: TX = 8, RX = 9

#define COPROC_STREAM 1 // Use SERIAL1_PORT definition

// Define step pulse output pins.
#define X_STEP_PORT GPIOD
#define X_STEP_PIN 4 // X
#define Y_STEP_PORT GPIOA
#define Y_STEP_PIN 15 // Y
#define Z_STEP_PORT GPIOE
#define Z_STEP_PIN 2 // Z
#define STEP_OUTMODE GPIO_SINGLE
//#define STEP_PINMODE PINMODE_OD // Uncomment for open drain outputs

// Define step direction output pins.
#define X_DIRECTION_PORT GPIOD
#define X_DIRECTION_PIN 3
#define Y_DIRECTION_PORT GPIOA
#define Y_DIRECTION_PIN 8
#define Z_DIRECTION_PORT GPIOE
#define Z_DIRECTION_PIN 3
#define DIRECTION_OUTMODE GPIO_SINGLE
//#define DIRECTION_PINMODE PINMODE_OD // Uncomment for open drain outputs

// Define stepper driver enable/disable output pin.
#define X_ENABLE_PORT GPIOD
#define X_ENABLE_PIN 6
#define Y_ENABLE_PORT GPIOD
#define Y_ENABLE_PIN 1
#define Z_ENABLE_PORT GPIOE
#define Z_ENABLE_PIN 0
//#define STEPPERS_ENABLE_PINMODE PINMODE_OD // Uncomment for open drain outputs

// Define homing/hard limit switch input pins.
#define X_LIMIT_PORT GPIOE
#define X_LIMIT_PIN 12 // EXP1
#define Y_LIMIT_PORT GPIOE
#define Y_LIMIT_PIN 10 // EXP1
#define Z_LIMIT_PORT GPIOC
#define Z_LIMIT_PIN 5 // EXP1
#define LIMIT_INMODE GPIO_SINGLE

/********** other limit switches ********/
// for the x axis, I am planning to make it auto-square so the M3 limit switch is the second x axis limit switch
// for the y axis, I will leave it as ganged axis so the m5 limit switch is the second y MAX limit switch
// Remaining undefined limit switch is the x max and the z max
// for the z axis max limit switch I have to manually define it
#define X_LIMIT_PORT_MAX GPIOE
#define X_LIMIT_PIN_MAX 9 // EXP1
#define Z_LIMIT_PORT_MAX GPIOB
#define Z_LIMIT_PIN_MAX 0 // EXP1

// Define ganged axis or A axis step pulse and step direction output pins.
#if N_ABC_MOTORS > 0
#define M3_AVAILABLE // E0
#define M3_STEP_PORT GPIOD
#define M3_STEP_PIN 15
#define M3_DIRECTION_PORT GPIOD
#define M3_DIRECTION_PIN 14
#define M3_LIMIT_PORT GPIOE //EXP1
#define M3_LIMIT_PIN 11
#define M3_ENABLE_PORT GPIOC
#define M3_ENABLE_PIN 7
#endif

// Define ganged axis or B axis step pulse and step direction output pins.
#if N_ABC_MOTORS == 2
#define M4_AVAILABLE // E1
#define M4_STEP_PORT GPIOD
#define M4_STEP_PIN 11
#define M4_DIRECTION_PORT GPIOD
#define M4_DIRECTION_PIN 10
/* // The normal limit pin for E1 is PA0, but bit 0 already has an interrupt (Z_LIMIT_PIN). /
/ // PC15 is normally used for PWRDET but is used for M4_LIMIT_PIN instead. /
/ // If using TMC drivers, jumper from PWRDET connector pin 3 to DIAG pin on driver. /
/ #define M4_LIMIT_PORT GPIOC // orig GPIOA /
/ #define M4_LIMIT_PIN 15 // orig 0 */

#define M4_LIMIT_PORT GPIOE
#define M4_LIMIT_PIN 8 // EXP1
#define M4_ENABLE_PORT GPIOD
#define M4_ENABLE_PIN 13
#endif

#define AUXOUTPUT0_PORT GPIOB // Spindle PWM - HE1
#define AUXOUTPUT0_PIN 4
#define AUXOUTPUT1_PORT GPIOB // Spindle direction - HE0
#define AUXOUTPUT1_PIN 3
#define AUXOUTPUT2_PORT GPIOA // Spindle enable - EXP2
#define AUXOUTPUT2_PIN 6
#define AUXOUTPUT3_PORT GPIOD // Coolant flood - HEAT0
#define AUXOUTPUT3_PIN 7
#define AUXOUTPUT4_PORT GPIOE // Coolant mist - HEAT1
#define AUXOUTPUT4_PIN 7

// Define driver spindle pins.
#if DRIVER_SPINDLE_ENABLE & SPINDLE_ENA
#define SPINDLE_ENABLE_PORT AUXOUTPUT2_PORT
#define SPINDLE_ENABLE_PIN AUXOUTPUT2_PIN
#endif
#if DRIVER_SPINDLE_ENABLE & SPINDLE_PWM
#define SPINDLE_PWM_PORT AUXOUTPUT0_PORT
#define SPINDLE_PWM_PIN AUXOUTPUT0_PIN
#endif
#if DRIVER_SPINDLE_ENABLE & SPINDLE_DIR
#define SPINDLE_DIRECTION_PORT AUXOUTPUT1_PORT
#define SPINDLE_DIRECTION_PIN AUXOUTPUT1_PIN
#endif

// Define flood and mist coolant enable output pins.
#if COOLANT_ENABLE & COOLANT_FLOOD
#define COOLANT_FLOOD_PORT AUXOUTPUT3_PORT
#define COOLANT_FLOOD_PIN AUXOUTPUT3_PIN
#endif
#if COOLANT_ENABLE & COOLANT_MIST
#define COOLANT_MIST_PORT AUXOUTPUT4_PORT
#define COOLANT_MIST_PIN AUXOUTPUT4_PIN
#endif

// Define user-control controls (cycle start, reset, feed hold) input pins.
// These are all available on EXP2 along with electrical RESET* (EXP2, pin 3)
/****** changing RESET_PIN, FEED_HOLD_PIN, CYCLE_START_PIN pin assignments /
/ #define CONTROL_PORT GPIOA /
/ #define RESET_PIN 4 // EXP2 - PA4, pin 7 /
/ #define FEED_HOLD_PIN 5 // EXP2 - PA5, pin 9 /
/ #define CYCLE_START_PIN 6 // EXP2 - PA6, pin 10 /
/ new values /
#define CONTROL_PORT GPIOA
#define RESET_PIN 1 // TB - PA1
#define FEED_HOLD_PIN 2 // TH0 - PA2
#define CYCLE_START_PIN 3 // TH1 - PA3
/********************************/

#define AUXINPUT0_PORT GPIOA
#define AUXINPUT0_PIN 7 // EXP2 - PA7, pin 5

#define AUXINPUT1_PORT GPIOC
#define AUXINPUT1_PIN 13 // Z probe

#if SAFETY_DOOR_ENABLE
#define SAFETY_DOOR_PORT AUXINPUT0_PORT
#define SAFETY_DOOR_PIN AUXINPUT0_PIN
#endif

#if PROBE_ENABLE
#define PROBE_PORT AUXINPUT1_PORT
#define PROBE_PIN AUXINPUT1_PIN
#endif

#define CONTROL_INMODE GPIO_SINGLE

#if TRINAMIC_UART_ENABLE

#define MOTOR_UARTX_PORT GPIOD
#define MOTOR_UARTX_PIN 5
#define MOTOR_UARTY_PORT GPIOD
#define MOTOR_UARTY_PIN 0
#define MOTOR_UARTZ_PORT GPIOE
#define MOTOR_UARTZ_PIN 1

#ifdef M3_AVAILABLE
#define MOTOR_UARTM3_PORT GPIOC
#define MOTOR_UARTM3_PIN 6
#endif

#ifdef M4_AVAILABLE
#define MOTOR_UARTM4_PORT GPIOD
#define MOTOR_UARTM4_PIN 12
#endif

#elif TRINAMIC_SPI_ENABLE

// The BTT SKR-3 uses software SPI
#define TRINAMIC_SOFT_SPI

#define TRINAMIC_MOSI_PORT GPIOE
#define TRINAMIC_MOSI_PIN 13
#define TRINAMIC_SCK_PORT GPIOE
#define TRINAMIC_SCK_PIN 14
#define TRINAMIC_MISO_PORT GPIOE
#define TRINAMIC_MISO_PIN 15

#define MOTOR_CSX_PORT GPIOD
#define MOTOR_CSX_PIN 5
#define MOTOR_CSY_PORT GPIOD
#define MOTOR_CSY_PIN 0
#define MOTOR_CSZ_PORT GPIOE
#define MOTOR_CSZ_PIN 1

#ifdef M3_AVAILABLE
#define MOTOR_CSM3_PORT GPIOC
#define MOTOR_CSM3_PIN 6
#endif

#ifdef M4_AVAILABLE
#define MOTOR_CSM4_PORT GPIOD
#define MOTOR_CSM4_PIN 12
#endif

[phil-barrett]

One option is to wire the max switch to the same side min limit switch. I've done this on my Avid Pro4848. Unless you have an application that needs to differentiate a max limit event from min limit one, it doesn't really matter which is triggered because either will stop your job.

Note that you wire NC vs NO switches together differently (series/parallel).

[terjeio]

There is one issue with this, if a limit switch is triggered and homing is called for the controller cannot determine which direction to pull off. To avoid damage set the Two switches shares one input option in the $22 (Homing cycle) setting. The controller will then refuse to carry out homing until limit switches are cleared.

[phil-barrett]

Good point.

[ambadran]

yeah, also I need to differentiate whether I hit min or max for my specific application, its really important for me. Is there another way to do it?