grbl/config.h

/*
  config.h - compile time configuration
  Part of Grbl

  Copyright (c) 2011-2014 Sungeun K. Jeon
  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 <http://www.gnu.org/licenses/>.
*/

// This file contains compile-time configurations for Grbl's internal system. For the most part,
// users will not need to directly modify these, but they are here for specific needs, i.e.
// performance tuning or adjusting to non-typical machines.

// IMPORTANT: Any changes here requires a full re-compiling of the source code to propagate them.

#ifndef config_h
#define config_h

// Default settings. Used when resetting EEPROM. Change to desired name in defaults.h
#define DEFAULTS_GENERIC

// Serial baud rate
#define BAUD_RATE 115200

// Default cpu mappings. Grbl officially supports the Arduino Uno only. Other processor types
// may exist from user-supplied templates or directly user-defined in cpu_map.h
#define CPU_MAP_ATMEGA328P // Arduino Uno CPU

// Define runtime command special characters. These characters are 'picked-off' directly from the
// serial read data stream and are not passed to the grbl line execution parser. Select characters
// that do not and must not exist in the streamed g-code program. ASCII control characters may be 
// used, if they are available per user setup. Also, extended ASCII codes (>127), which are never in 
// g-code programs, maybe selected for interface programs.
// NOTE: If changed, manually update help message in report.c.
#define CMD_STATUS_REPORT '?'
#define CMD_FEED_HOLD '!'
#define CMD_CYCLE_START '~'
#define CMD_RESET 0x18 // ctrl-x.

// If homing is enabled, homing init lock sets Grbl into an alarm state upon power up. This forces
// the user to perform the homing cycle (or override the locks) before doing anything else. This is
// mainly a safety feature to remind the user to home, since position is unknown to Grbl.
#define HOMING_INIT_LOCK // Comment to disable

// Define the homing cycle patterns with bitmasks. The homing cycle first performs a search mode
// to quickly engage the limit switches, followed by a slower locate mode, and finished by a short
// pull-off motion to disengage the limit switches. The following HOMING_CYCLE_x defines are executed 
// in order starting with suffix 0 and completes the homing routine for the specified-axes only. If
// an axis is omitted from the defines, it will not home, nor will the system update its position.
// Meaning that this allows for users with non-standard cartesian machines, such as a lathe (x then z,
// with no y), to configure the homing cycle behavior to their needs. 
// NOTE: The homing cycle is designed to allow sharing of limit pins, if the axes are not in the same
// cycle, but this requires some pin settings changes in cpu_map.h file. For example, the default homing
// cycle can share the Z limit pin with either X or Y limit pins, since they are on different cycles.
// By sharing a pin, this frees up a precious IO pin for other purposes. In theory, all axes limit pins
// may be reduced to one pin, if all axes are homed with seperate cycles, or vice versa, all three axes
// on separate pin, but homed in one cycle. Also, it should be noted that the function of hard limits 
// will not be affected by pin sharing.
// NOTE: Defaults are set for a traditional 3-axis CNC machine. Z-axis first to clear, followed by X & Y.
#define HOMING_CYCLE_0 (1<<Z_AXIS)                // REQUIRED: First move Z to clear workspace.
#define HOMING_CYCLE_1 ((1<<X_AXIS)|(1<<Y_AXIS))  // OPTIONAL: Then move X,Y at the same time.
// #define HOMING_CYCLE_2                         // OPTIONAL: Uncomment and add axes mask to enable

// Number of homing cycles performed after when the machine initially jogs to limit switches.
// This help in preventing overshoot and should improve repeatability. This value should be one or 
// greater.
#define N_HOMING_LOCATE_CYCLE 2 // Integer (1-128)

// Number of blocks Grbl executes upon startup. These blocks are stored in EEPROM, where the size
// and addresses are defined in settings.h. With the current settings, up to 3 startup blocks may
// be stored and executed in order. These startup blocks would typically be used to set the g-code
// parser state depending on user preferences.
#define N_STARTUP_LINE 2 // Integer (1-3)

// Allows GRBL to tranck and report gcode line numbers.  Enabling this means that the planning buffer
// goes from 18 or 16 to make room for the additional line number data in the plan_block_t struct
// #define USE_LINE_NUMBERS // Disabled by default. Uncomment to enable.

// Enables a second coolant control pin via the mist coolant g-code command M7 on the Arduino Uno
// analog pin 5. Only use this option if you require a second coolant control pin.
// NOTE: The M8 flood coolant control pin on analog pin 4 will still be functional regardless.
// #define ENABLE_M7 // Disabled by default. Uncomment to enable.

// ---------------------------------------------------------------------------------------
// ADVANCED CONFIGURATION OPTIONS:

// The temporal resolution of the acceleration management subsystem. A higher number gives smoother
// acceleration, particularly noticeable on machines that run at very high feedrates, but may negatively
// impact performance. The correct value for this parameter is machine dependent, so it's advised to
// set this only as high as needed. Approximate successful values can widely range from 50 to 200 or more.
// NOTE: Changing this value also changes the execution time of a segment in the step segment buffer. 
// When increasing this value, this stores less overall time in the segment buffer and vice versa. Make
// certain the step segment buffer is increased/decreased to account for these changes.
#define ACCELERATION_TICKS_PER_SECOND 100 

// Adaptive Multi-Axis Step Smoothing (AMASS) is an advanced feature that does what its name implies, 
// smoothing the stepping of multi-axis motions. This feature smooths motion particularly at low step
// frequencies below 10kHz, where the aliasing between axes of multi-axis motions can cause audible 
// noise and shake your machine. At even lower step frequencies, AMASS adapts and provides even better
// step smoothing. See stepper.c for more details on the AMASS system works.
#define ADAPTIVE_MULTI_AXIS_STEP_SMOOTHING  // Default enabled. Comment to disable.

// Enables variable spindle output voltage for different RPM values. On the Arduino Uno, the spindle
// enable pin will output 5V for maximum RPM with 256 intermediate levels and 0V when disabled.
// NOTE: IMPORTANT for Arduino Unos! When enabled, the Z-limit pin D11 and spindle enable pin D12 switch!
// The hardware PWM output on pin D11 is required for variable spindle output voltages.
// #define VARIABLE_SPINDLE // Default disabled. Uncomment to enable.

// Use by the variable spindle output only. These parameters set the maximum and minimum spindle speed
// "S" g-code values to correspond to the maximum and minimum pin voltages. There are 256 discrete and 
// equally divided voltage bins between the maximum and minimum spindle speeds. So for a 5V pin, 1000
// max rpm, and 250 min rpm, the spindle output voltage would be set for the following "S" commands: 
// "S1000" @ 5V, "S250" @ 0.02V, and "S625" @ 2.5V (mid-range). The pin outputs 0V when disabled.
#define SPINDLE_MAX_RPM 1000.0 // Max spindle RPM. This value is equal to 100% duty cycle on the PWM.
#define SPINDLE_MIN_RPM 0.0    // Min spindle RPM. This value is equal to (1/256) duty cycle on the PWM.

// Minimum planner junction speed. Sets the default minimum junction speed the planner plans to at
// every buffer block junction, except for starting from rest and end of the buffer, which are always
// zero. This value controls how fast the machine moves through junctions with no regard for acceleration
// limits or angle between neighboring block line move directions. This is useful for machines that can't
// tolerate the tool dwelling for a split second, i.e. 3d printers or laser cutters. If used, this value
// should not be much greater than zero or to the minimum value necessary for the machine to work.
#define MINIMUM_JUNCTION_SPEED 0.0 // (mm/min)

// Number of arc generation iterations by small angle approximation before exact arc trajectory 
// correction. This parameter maybe decreased if there are issues with the accuracy of the arc
// generations. In general, the default value is more than enough for the intended CNC applications
// of grbl, and should be on the order or greater than the size of the buffer to help with the 
// computational efficiency of generating arcs.
// NOTE: Arcs are now generated by a chordal tolerance
#define N_ARC_CORRECTION 20 // Integer (1-255)

// Time delay increments performed during a dwell. The default value is set at 50ms, which provides
// a maximum time delay of roughly 55 minutes, more than enough for most any application. Increasing
// this delay will increase the maximum dwell time linearly, but also reduces the responsiveness of 
// run-time command executions, like status reports, since these are performed between each dwell 
// time step. Also, keep in mind that the Arduino delay timer is not very accurate for long delays.
#define DWELL_TIME_STEP 50 // Integer (1-255) (milliseconds)

// Creates a delay between the direction pin setting and corresponding step pulse by creating
// another interrupt (Timer2 compare) to manage it. The main Grbl interrupt (Timer1 compare) 
// sets the direction pins, and does not immediately set the stepper pins, as it would in 
// normal operation. The Timer2 compare fires next to set the stepper pins after the step 
// pulse delay time, and Timer2 overflow will complete the step pulse, except now delayed 
// by the step pulse time plus the step pulse delay. (Thanks langwadt for the idea!)
// NOTE: Uncomment to enable. The recommended delay must be > 3us, and, when added with the
// user-supplied step pulse time, the total time must not exceed 127us. Reported successful
// values for certain setups have ranged from 5 to 20us.
// #define STEP_PULSE_DELAY 10 // Step pulse delay in microseconds. Default disabled.

// The number of linear motions in the planner buffer to be planned at any give time. The vast
// majority of RAM that Grbl uses is based on this buffer size. Only increase if there is extra 
// available RAM, like when re-compiling for a Mega or Sanguino. Or decrease if the Arduino
// begins to crash due to the lack of available RAM or if the CPU is having trouble keeping
// up with planning new incoming motions as they are executed. 
// #define BLOCK_BUFFER_SIZE 18  // Uncomment to override default in planner.h.

// Governs the size of the intermediary step segment buffer between the step execution algorithm
// and the planner blocks. Each segment is set of steps executed at a constant velocity over a
// fixed time defined by ACCELERATION_TICKS_PER_SECOND. They are computed such that the planner
// block velocity profile is traced exactly. The size of this buffer governs how much step 
// execution lead time there is for other Grbl processes have to compute and do their thing 
// before having to come back and refill this buffer, currently at ~50msec of step moves.
// #define SEGMENT_BUFFER_SIZE 6 // Uncomment to override default in stepper.h.

// Line buffer size from the serial input stream to be executed. Also, governs the size of 
// each of the startup blocks, as they are each stored as a string of this size. Make sure
// to account for the available EEPROM at the defined memory address in settings.h and for
// the number of desired startup blocks.
// NOTE: 70 characters is not a problem except for extreme cases, but the line buffer size 
// can be too small and g-code blocks can get truncated. Officially, the g-code standards 
// support up to 256 characters. In future versions, this default will be increased, when 
// we know how much extra memory space we can re-invest into this.
// #define LINE_BUFFER_SIZE 70  // Uncomment to override default in protocol.h
  
// Serial send and receive buffer size. The receive buffer is often used as another streaming
// buffer to store incoming blocks to be processed by Grbl when its ready. Most streaming
// interfaces will character count and track each block send to each block response. So, 
// increase the receive buffer if a deeper receive buffer is needed for streaming and avaiable
// memory allows. The send buffer primarily handles messages in Grbl. Only increase if large
// messages are sent and Grbl begins to stall, waiting to send the rest of the message.
// #define RX_BUFFER_SIZE 128 // Uncomment to override defaults in serial.h
// #define TX_BUFFER_SIZE 64
  
// Toggles XON/XOFF software flow control for serial communications. Not officially supported
// due to problems involving the Atmega8U2 USB-to-serial chips on current Arduinos. The firmware
// on these chips do not support XON/XOFF flow control characters and the intermediate buffer 
// in the chips cause latency and overflow problems with standard terminal programs. However, 
// using specifically-programmed UI's to manage this latency problem has been confirmed to work.
// As well as, older FTDI FT232RL-based Arduinos(Duemilanove) are known to work with standard
// terminal programs since their firmware correctly manage these XON/XOFF characters. In any
// case, please report any successes to grbl administrators!
// #define ENABLE_XONXOFF // Default disabled. Uncomment to enable.

// A simple software debouncing feature for hard limit switches. When enabled, the interrupt 
// monitoring the hard limit switch pins will enable the Arduino's watchdog timer to re-check 
// the limit pin state after a delay of about 32msec. This can help with CNC machines with 
// problematic false triggering of their hard limit switches, but it WILL NOT fix issues with 
// electrical interference on the signal cables from external sources. It's recommended to first
// use shielded signal cables with their shielding connected to ground (old USB/computer cables 
// work well and are cheap to find) and wire in a low-pass circuit into each limit pin.
// #define ENABLE_SOFTWARE_DEBOUNCE // Default disabled. Uncomment to enable.

// ---------------------------------------------------------------------------------------

// TODO: Install compile-time option to send numeric status codes rather than strings.

// ---------------------------------------------------------------------------------------
// COMPILE-TIME ERROR CHECKING OF DEFINE VALUES:

// #if (ISR_TICKS_PER_ACCELERATION_TICK > 255)
// #error Parameters ACCELERATION_TICKS / ISR_TICKS must be < 256 to prevent integer overflow.
// #endif

// ---------------------------------------------------------------------------------------
#endif