samd/boards: Add two SparkFun SAMD21 boards.

Add support for the boards:
- SparkFun SAMD21 Dev Breakout
- SparkFun RedBoard Turbo

Both boards are SAMD21 based and actively sold by SparkFun.

Signed-off-by: robert-hh <robert@hammelrath.com>

ports/samd/boards/SPARKFUN_REDBOARD_TURBO/board.json

@@ -0,0 +1,21 @@
+{
+    "deploy": [
+        "../deploy.md"
+    ],
+    "docs": "",
+    "features": [
+        "Battery Charging",
+        "DAC",
+        "External Flash",
+        "USB",
+        "RGB LED"
+    ],
+    "images": [
+        "sparkfun_readboard_turbo.jpg"
+    ],
+    "mcu": "samd21",
+    "product": "SparkFun RedBoard Turbo",
+    "thumbnail": "",
+    "url": "https://www.sparkfun.com/products/14812",
+    "vendor": "Sparkfun"
+}

ports/samd/boards/SPARKFUN_REDBOARD_TURBO/mpconfigboard.h

@@ -0,0 +1,11 @@
+#define MICROPY_HW_BOARD_NAME "SparkFun RedBoard Turbo"
+#define MICROPY_HW_MCU_NAME   "SAMD21G18A"
+
+#define MICROPY_HW_XOSC32K     (1)
+
+#define MICROPY_HW_SPIFLASH    (1)
+#define MICROPY_HW_SPIFLASH_ID (5)
+
+#define MICROPY_HW_DEFAULT_UART_ID  (0)
+#define MICROPY_HW_DEFAULT_I2C_ID   (3)
+#define MICROPY_HW_DEFAULT_SPI_ID   (4)

ports/samd/boards/SPARKFUN_REDBOARD_TURBO/mpconfigboard.mk

@@ -0,0 +1,8 @@
+MCU_SERIES = SAMD21
+CMSIS_MCU = SAMD21G18A
+LD_FILES = boards/samd21x18a.ld sections.ld
+TEXT0 = 0x2000
+
+# The ?='s allow overriding in mpconfigboard.mk.
+# MicroPython settings
+MICROPY_HW_CODESIZE ?= 232K

ports/samd/boards/SPARKFUN_REDBOARD_TURBO/pins.csv

@@ -0,0 +1,47 @@
+# The lines contain pairs of Pin name and Pin number.
+# Pin names must be valid Python identifiers.
+# Pin numbers have the form Pxnn, with x being A, B, C or D.
+# Lines starting with # or empty lines are ignored.
+
+USB_DM,PA24
+USB_DP,PA25
+
+SWCLK,PA30
+SWDIO,PA31
+
+D0,PA11
+D1,PA10
+D2,PA14
+D3,PA09
+D4,PA08
+D5,PA15
+D6,PA20
+D7,PA21
+D8,PA06
+D9,PA07
+D10,PA18
+D11,PA16
+D12,PA19
+D13,PA17
+A0,PA02
+A1,PB08
+A2,PB09
+A3,PA04
+A4,PA05
+A5,PB02
+AREF,PA03
+RX,PA11
+TX,PA10
+SCL,PA23
+SDA,PA22
+MOSI,PB10
+MISO,PA12
+SCK,PB11
+FLASH_MOSI,PB22
+FLASH_MISO,PB03
+FLASH_SCK,PB23
+FLASH_CS,PA13
+NEOPIXEL,PA30
+
+LED_TX,PA27
+LED_RX,PA31

ports/samd/boards/SPARKFUN_SAMD21_DEV_BREAKOUT/board.json

@@ -0,0 +1,19 @@
+{
+    "deploy": [
+        "../deploy.md"
+    ],
+    "docs": "",
+    "features": [
+        "Battery Charging",
+        "DAC",
+        "USB"
+    ],
+    "images": [
+        "sparkfun_sam21_dev_breakout.jpg"
+    ],
+    "mcu": "samd21",
+    "product": "SparkFun SAMD21 Dev Breakout",
+    "thumbnail": "",
+    "url": "https://www.sparkfun.com/products/13672",
+    "vendor": "Sparkfun"
+}

ports/samd/boards/SPARKFUN_SAMD21_DEV_BREAKOUT/mpconfigboard.h

@@ -0,0 +1,8 @@
+#define MICROPY_HW_BOARD_NAME "SparkFun SAMD21 Dev Breakout"
+#define MICROPY_HW_MCU_NAME   "SAMD21G18A"
+
+#define MICROPY_HW_XOSC32K          (1)
+
+#define MICROPY_HW_DEFAULT_UART_ID  (0)
+#define MICROPY_HW_DEFAULT_I2C_ID   (3)
+#define MICROPY_HW_DEFAULT_SPI_ID   (4)

ports/samd/boards/SPARKFUN_SAMD21_DEV_BREAKOUT/mpconfigboard.mk

@@ -0,0 +1,4 @@
+MCU_SERIES = SAMD21
+CMSIS_MCU = SAMD21G18A
+LD_FILES = boards/samd21x18a.ld sections.ld
+TEXT0 = 0x2000

ports/samd/boards/SPARKFUN_SAMD21_DEV_BREAKOUT/pins.csv

@@ -0,0 +1,45 @@
+# The lines contain pairs of Pin name and Pin number.
+# Pin names must be valid Python identifiers.
+# Pin numbers have the form Pxnn, with x being A, B, C or D.
+# Lines starting with # or empty lines are ignored.
+
+USB_DM,PA24
+USB_DP,PA25
+
+SWCLK,PA30
+SWDIO,PA31
+
+D0,PA11
+D1,PA10
+D2,PA14
+D3,PA09
+D4,PA08
+D5,PA15
+D6,PA20
+D7,PA21
+D8,PA06
+D9,PA07
+D10,PA18
+D11,PA16
+D12,PA19
+D13,PA17
+A0,PA02
+A1,PB08
+A2,PB09
+A3,PA04
+A4,PA05
+A5,PB02
+AREF,PA03
+RX,PA11
+TX,PA10
+SCL,PA23
+SDA,PA22
+MOSI,PB10
+MISO,PA12
+SCK,PB11
+D38,PA13
+D30,PB22
+D31,PB23
+
+LED_TX,PA27
+LED_RX,PB03