Reworked @jusjoheinz 's TMC support from https://github.com/justjoheinz/grbl/tree/trinamic into master of Grbl 0.9J

Makefile

@@ -33,7 +33,7 @@ CLOCK      = 16000000
 PROGRAMMER ?= -c avrisp2 -P usb
 SOURCE    = main.c motion_control.c gcode.c spindle_control.c coolant_control.c serial.c \
              protocol.c stepper.c eeprom.c settings.c planner.c nuts_bolts.c limits.c \
-             print.c probe.c report.c system.c
+             print.c probe.c report.c system.c trinamic.c spi.c
 BUILDDIR = build
 SOURCEDIR = grbl
 # FUSES      = -U hfuse:w:0xd9:m -U lfuse:w:0x24:m

Makefile~

@@ -0,0 +1,100 @@
+#  Part of Grbl
+#
+#  Copyright (c) 2009-2011 Simen Svale Skogsrud
+#  Copyright (c) 2012-2015 Sungeun K. Jeon
+#
+#  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 is a prototype Makefile. Modify it according to your needs.
+# You should at least check the settings for
+# DEVICE ....... The AVR device you compile for
+# CLOCK ........ Target AVR clock rate in Hertz
+# OBJECTS ...... The object files created from your source files. This list is
+#                usually the same as the list of source files with suffix ".o".
+# PROGRAMMER ... Options to avrdude which define the hardware you use for
+#                uploading to the AVR and the interface where this hardware
+#                is connected.
+# FUSES ........ Parameters for avrdude to flash the fuses appropriately.
+
+DEVICE     ?= atmega328p
+CLOCK      = 16000000
+PROGRAMMER ?= -c avrisp2 -P usb
+SOURCE    = main.c motion_control.c gcode.c spindle_control.c coolant_control.c serial.c \
+             protocol.c stepper.c eeprom.c settings.c planner.c nuts_bolts.c limits.c \
+             print.c probe.c report.c system.c
+BUILDDIR = build
+SOURCEDIR = grbl
+# FUSES      = -U hfuse:w:0xd9:m -U lfuse:w:0x24:m
+FUSES      = -U hfuse:w:0xd2:m -U lfuse:w:0xff:m
+
+# Tune the lines below only if you know what you are doing:
+
+AVRDUDE = avrdude $(PROGRAMMER) -p $(DEVICE) -B 10 -F
+COMPILE = avr-gcc -Wall -Os -DF_CPU=$(CLOCK) -mmcu=$(DEVICE) -I. -ffunction-sections -fdata-sections
+
+OBJECTS = $(addprefix $(BUILDDIR)/,$(notdir $(SOURCE:.c=.o)))
+
+# symbolic targets:
+all:	grbl.hex
+
+$(BUILDDIR)/%.o: $(SOURCEDIR)/%.c
+	$(COMPILE) -MMD -MP -c $< -o $@
+
+.S.o:
+	$(COMPILE) -x assembler-with-cpp -c $< -o $(BUILDDIR)/$@
+# "-x assembler-with-cpp" should not be necessary since this is the default
+# file type for the .S (with capital S) extension. However, upper case
+# characters are not always preserved on Windows. To ensure WinAVR
+# compatibility define the file type manually.
+
+#.c.s:
+	$(COMPILE) -S $< -o $(BUILDDIR)/$@
+
+flash:	all
+	$(AVRDUDE) -U flash:w:grbl.hex:i
+
+fuse:
+	$(AVRDUDE) $(FUSES)
+
+# Xcode uses the Makefile targets "", "clean" and "install"
+install: flash fuse
+
+# if you use a bootloader, change the command below appropriately:
+load: all
+	bootloadHID grbl.hex
+
+clean:
+	rm -f grbl.hex $(BUILDDIR)/*.o $(BUILDDIR)/*.d $(BUILDDIR)/*.elf
+
+# file targets:
+$(BUILDDIR)/main.elf: $(OBJECTS)
+	$(COMPILE) -o $(BUILDDIR)/main.elf $(OBJECTS) -lm -Wl,--gc-sections
+
+grbl.hex: $(BUILDDIR)/main.elf
+	rm -f grbl.hex
+	avr-objcopy -j .text -j .data -O ihex $(BUILDDIR)/main.elf grbl.hex
+	avr-size --format=berkeley $(BUILDDIR)/main.elf
+# If you have an EEPROM section, you must also create a hex file for the
+# EEPROM and add it to the "flash" target.
+
+# Targets for code debugging and analysis:
+disasm:	main.elf
+	avr-objdump -d $(BUILDDIR)/main.elf
+
+cpp:
+	$(COMPILE) -E $(SOURCEDIR)/main.c
+
+# include generated header dependencies
+-include $(BUILDDIR)/$(OBJECTS:.o=.d)

grbl/config.h

@@ -31,7 +31,8 @@
 
 
 // Default settings. Used when resetting EEPROM. Change to desired name in defaults.h
-#define DEFAULTS_GENERIC
+//#define DEFAULTS_GENERIC
+#define DEFAULTS_TRINAMIC
 
 // Serial baud rate
 #define BAUD_RATE 115200
@@ -236,7 +237,7 @@
 // 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 enabled. Comment to disable.
+#define VARIABLE_SPINDLE // Default enabled. Comment to disable. // TRINAMIC - TESTIng
 
 // Used 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 
@@ -260,7 +261,7 @@
 // NOTE: BEWARE! The Arduino bootloader toggles the D13 pin when it powers up. If you flash Grbl with
 // a programmer (you can use a spare Arduino as "Arduino as ISP". Search the web on how to wire this.), 
 // this D13 LED toggling should go away. We haven't tested this though. Please report how it goes!
-// #define USE_SPINDLE_DIR_AS_ENABLE_PIN // Default disabled. Uncomment to enable.
+ #define USE_SPINDLE_DIR_AS_ENABLE_PIN // Default disabled. Uncomment to enable.
 
 // With this enabled, Grbl sends back an echo of the line it has received, which has been pre-parsed (spaces
 // removed, capitalized letters, no comments) and is to be immediately executed by Grbl. Echoes will not be 
@@ -269,7 +270,7 @@
 // NOTE: Only use this for debugging purposes!! When echoing, this takes up valuable resources and can effect
 // performance. If absolutely needed for normal operation, the serial write buffer should be greatly increased
 // to help minimize transmission waiting within the serial write protocol.
-// #define REPORT_ECHO_LINE_RECEIVED // Default disabled. Uncomment to enable.
+ #define REPORT_ECHO_LINE_RECEIVED // Default disabled. Uncomment to enable.
 
 // 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