/* stepper.c - stepper motor driver: executes motion plans using stepper motors Part of Grbl Copyright (c) 2009-2011 Simen Svale Skogsrud Grbl is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. Grbl is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Grbl. If not, see . */ /* The timer calculations of this module informed by the 'RepRap cartesian firmware' by Zack Smith and Philipp Tiefenbacher. The ring buffer implementation gleaned from the wiring_serial library by David A. Mellis */ #include "stepper.h" #include "config.h" #include "settings.h" #include #include #include #include "nuts_bolts.h" #include #include "stepper_plan.h" #include "wiring_serial.h" // Some useful constants #define STEP_MASK ((1< // // The trapezoid is the shape the speed curve over time. It starts at block->initial_rate, accelerates by block->rate_delta // during the first block->accelerate_until step_events_completed, then keeps going at constant speed until // step_events_completed reaches block->decelerate_after after which it decelerates until the trapezoid generator is reset. // The slope of acceleration is always +/- block->rate_delta and is applied at a constant rate by trapezoid_generator_tick() // that is called ACCELERATION_TICKS_PER_SECOND times per second. void set_step_events_per_minute(uint32_t steps_per_minute); // Initializes the trapezoid generator from the current block. Called whenever a new // block begins. inline void trapezoid_generator_reset() { trapezoid_adjusted_rate = current_block->initial_rate; set_step_events_per_minute(trapezoid_adjusted_rate); } // This is called ACCELERATION_TICKS_PER_SECOND times per second by the step_event // interrupt. It can be assumed that the trapezoid-generator-parameters and the // current_block stays untouched by outside handlers for the duration of this function call. inline void trapezoid_generator_tick() { if (current_block) { if (step_events_completed < current_block->accelerate_until) { trapezoid_adjusted_rate += current_block->rate_delta; set_step_events_per_minute(trapezoid_adjusted_rate); } else if (step_events_completed > current_block->decelerate_after) { // NOTE: We will only reduce speed if the result will be > 0. This catches small // rounding errors that might leave steps hanging after the last trapezoid tick. if(current_block->rate_delta < trapezoid_adjusted_rate) { trapezoid_adjusted_rate -= current_block->rate_delta; } set_step_events_per_minute(trapezoid_adjusted_rate); } } } // Add a new linear movement to the buffer. steps_x, _y and _z is the signed, relative motion in // steps. Microseconds specify how many microseconds the move should take to perform. To aid acceleration // calculation the caller must also provide the physical length of the line in millimeters. void st_buffer_line(double x, double y, double z, double feed_rate, int invert_feed_rate) { plan_buffer_line(x, y, z, feed_rate, invert_feed_rate); // Ensure that block processing is running by enabling The Stepper Driver Interrupt ENABLE_STEPPER_DRIVER_INTERRUPT(); } void st_get_position_steps(int32_t (*vector)[3]) { memcpy(vector, position, sizeof(position)); // vector[] = position[] } // "The Stepper Driver Interrupt" - This timer interrupt is the workhorse of Grbl. It is executed at the rate set with // config_step_timer. It pops blocks from the block_buffer and executes them by pulsing the stepper pins appropriately. // It is supported by The Stepper Port Reset Interrupt which it uses to reset the stepper port after each pulse. SIGNAL(TIMER1_COMPA_vect) { // TODO: Check if the busy-flag can be eliminated by just disabeling this interrupt while we are in it if(busy){ return; } // The busy-flag is used to avoid reentering this interrupt // Set the direction pins a cuple of nanoseconds before we step the steppers STEPPING_PORT = (STEPPING_PORT & ~DIRECTION_MASK) | (out_bits & DIRECTION_MASK); // Then pulse the stepping pins STEPPING_PORT = (STEPPING_PORT & ~STEP_MASK) | out_bits; // Reset step pulse reset timer so that The Stepper Port Reset Interrupt can reset the signal after // exactly settings.pulse_microseconds microseconds. TCNT2 = -(((settings.pulse_microseconds-2)*TICKS_PER_MICROSECOND)/8); busy = TRUE; sei(); // Re enable interrupts (normally disabled while inside an interrupt handler) // ((We re-enable interrupts in order for SIG_OVERFLOW2 to be able to be triggered // at exactly the right time even if we occasionally spend a lot of time inside this handler.)) // If there is no current block, attempt to pop one from the buffer if (current_block == NULL) { // Anything in the buffer? current_block = plan_get_current_block(); if (current_block != NULL) { trapezoid_generator_reset(); counter_x = -(current_block->step_event_count >> 1); counter_y = counter_x; counter_z = counter_x; step_events_completed = 0; } else { DISABLE_STEPPER_DRIVER_INTERRUPT(); } } if (current_block != NULL) { out_bits = current_block->direction_bits; counter_x += current_block->steps_x; if (counter_x > 0) { out_bits |= (1<step_event_count; } counter_y += current_block->steps_y; if (counter_y > 0) { out_bits |= (1<step_event_count; } counter_z += current_block->steps_z; if (counter_z > 0) { out_bits |= (1<step_event_count; } // If current block is finished, reset pointer step_events_completed += 1; if (step_events_completed >= current_block->step_event_count) { // printInteger(current_block->exit_rate); // printString(" == "); // printInteger(trapezoid_adjusted_rate); // printString(" <-- exit, actual\n\r"); // printInteger(current_block->rate_delta); // printString(" <-- delta\n\r"); current_block = NULL; plan_discard_current_block(); } } else { out_bits = 0; } out_bits ^= settings.invert_mask; // In average this generates a trapezoid_generator_tick every CYCLES_PER_ACCELERATION_TICK by keeping track // of the number of elapsed cycles. The code assumes that step_events occur significantly more often than // trapezoid_generator_ticks as they well should. trapezoid_tick_cycle_counter += cycles_per_step_event; if(trapezoid_tick_cycle_counter > CYCLES_PER_ACCELERATION_TICK) { trapezoid_tick_cycle_counter -= CYCLES_PER_ACCELERATION_TICK; trapezoid_generator_tick(); } busy=FALSE; } // This interrupt is set up by SIG_OUTPUT_COMPARE1A when it sets the motor port bits. It resets // the motor port after a short period (settings.pulse_microseconds) completing one step cycle. SIGNAL(TIMER2_OVF_vect) { // reset stepping pins (leave the direction pins) STEPPING_PORT = (STEPPING_PORT & ~STEP_MASK) | (settings.invert_mask & STEP_MASK); } // Initialize and start the stepper motor subsystem void st_init() { // Configure directions of interface pins STEPPING_DDR |= STEPPING_MASK; STEPPING_PORT = (STEPPING_PORT & ~STEPPING_MASK) | settings.invert_mask; LIMIT_DDR &= ~(LIMIT_MASK); STEPPERS_ENABLE_DDR |= 1<> 3; prescaler = 1; // prescaler: 8 actual_cycles = ceiling * 8L; } else if (cycles <= 0x3fffffL) { ceiling = cycles >> 6; prescaler = 2; // prescaler: 64 actual_cycles = ceiling * 64L; } else if (cycles <= 0xffffffL) { ceiling = (cycles >> 8); prescaler = 3; // prescaler: 256 actual_cycles = ceiling * 256L; } else if (cycles <= 0x3ffffffL) { ceiling = (cycles >> 10); prescaler = 4; // prescaler: 1024 actual_cycles = ceiling * 1024L; } else { // Okay, that was slower than we actually go. Just set the slowest speed ceiling = 0xffff; prescaler = 4; actual_cycles = 0xffff * 1024; } // Set prescaler TCCR1B = (TCCR1B & ~(0x07<