Add support for REPL on Arduino Zero through EDBG via UART.

Author: tannewt

atmel-samd/.gitattributes

@@ -0,0 +1 @@
+tools/bossac* binary

atmel-samd/Makefile

@@ -1,6 +1,6 @@
 # Select the board to build for: if not given on the command line,
 # then default to PYBV10.
-BOARD ?= feather_m0_ble
+BOARD ?= arduino_zero
 ifeq ($(wildcard boards/$(BOARD)/.),)
 $(error Invalid BOARD specified)
 endif
@@ -54,6 +54,7 @@ INC +=  $(addprefix -Iasf/sam0/,\
 	drivers/system/pinmux \
 	drivers/system/power/power_sam_d_r \
 	drivers/system/reset/reset_sam_d_r \
+	drivers/sercom/ \
 	drivers/usb/ \
 	utils \
 	utils/cmsis/samd21/include \
@@ -92,8 +93,13 @@ endif
 
 SRC_ASF = $(addprefix asf/sam0/,\
 	drivers/port/port.c \
+	drivers/sercom/sercom.c \
+	drivers/sercom/sercom_interrupt.c \
+	drivers/sercom/usart/usart.c \
+	drivers/sercom/usart/usart_interrupt.c \
 	drivers/system/clock/clock_samd21_r21_da/clock.c \
 	drivers/system/clock/clock_samd21_r21_da/gclk.c \
+	drivers/system/interrupt/system_interrupt.c   \
 	drivers/system/pinmux/pinmux.c \
 	drivers/system/system.c \
 	drivers/usb/stack_interface/usb_device_udd.c \
@@ -104,12 +110,16 @@ SRC_ASF = $(addprefix asf/sam0/,\
 SRC_C = \
 	main.c \
 	mphalport.c \
+	uart.c \
 	asf/common/services/sleepmgr/samd/sleepmgr.c \
 	asf/common/services/usb/class/cdc/device/udi_cdc.c \
 	asf/common/services/usb/class/cdc/device/udi_cdc_desc.c \
 	asf/common/services/usb/udc/udc.c \
 	asf/common/utils/interrupt/interrupt_sam_nvic.c \
 	asf/common2/services/delay/sam0/systick_counter.c \
+	asf/sam0/utils/cmsis/samd21/source/gcc/startup_samd21.c \
+	asf/sam0/utils/cmsis/samd21/source/system_samd21.c     \
+	asf/sam0/utils/syscalls/gcc/syscalls.c \
 	lib/utils/stdout_helpers.c \
 	lib/utils/printf.c \
 	lib/utils/pyexec.c \
@@ -137,7 +147,7 @@ $(BUILD)/firmware.elf: $(OBJ)
 
 $(BUILD)/firmware.bin: $(BUILD)/firmware.elf
 	$(ECHO) "Create $@"
-	$(Q)$(OBJCOPY) -O binary -j .isr_vector -j .text -j .data $^ $@
+	$(Q)$(OBJCOPY) -O binary -j .vectors -j .text -j .data $^ $@
 
 deploy: $(BUILD)/firmware.bin
 	$(ECHO) "Writing $< to the board"

atmel-samd/README.md

@@ -4,14 +4,47 @@ This port is intended to be a full featured MicroPython port for SAMD21x18 based
 development boards including the Arduino Zero, Adafruit Feather M0 and Adafruit
 M0 BLE.
 
-## Building for a SAMD21x18 MCU
+## Building
 
 The Makefile has the ability to build for a SAMD21x18, and by default
 includes some start-up code and also enables a UART for communication.  To build:
 
-    $ make CROSS=1
+    make CROSS=1
 
-If you previously built the Linux version, you will need to first run
-`make clean` to get rid of incompatible object files.
+It will build for the Arduino Zero by default. You may change it by setting `BOARD`. For example:
 
-Deploying coming soon!
+    make CROSS=1 BOARD=feather_m0_ble
+
+Board names are the directory names in the `boards` folder.
+
+## Deploying
+
+### Arduino Bootloader
+If your board has an existing Arduino bootloader on it then you can use bossac to flash MicroPython. After building run:
+
+    tools/bossac_osx -e -w -v -b build-feather_m0_ble/firmware.bin
+
+### No Bootloader via GDB
+This method works for loading MicroPython onto the Arduino Zero via the programming port rather than the native USB port.
+
+Note: These instructions are tested on Mac OSX and will vary for different platforms.
+
+    openocd -f ~/Library/Arduino15/packages/arduino/hardware/samd/1.6.6/variants/arduino_zero/openocd_scripts/arduino_zero.cfg
+
+In another terminal from `micropython/atmel-samd`:
+
+    arm-none-eabi-gdb build-arduino_zero/firmware.elf
+    (gdb) tar ext :3333
+    ...
+    (gdb) load
+    ...
+    (gdb) monitor reset init
+    ...
+    (gdb) continue
+
+## Connecting
+The current Atmel SAMD implementation only works over UART. To connect to it from OSX do something like this:
+
+    screen /dev/tty.usbmodem142422 115200
+
+You may not see a prompt immediately because it doesn't know you connected. To get one either hit enter to get `>>>` or do CTRL-B to get the full header.