samd: Add board definition for Sparkfun SAMD51 MicroMod.

Signed-off-by: Andrew Teta <andrew.teta@gmail.com>

ports/samd/boards/SPARKFUN_SAMD51_MICROMOD/board.json

@@ -0,0 +1,19 @@
+{
+    "deploy": [
+        "../deploy.md"
+    ],
+    "docs": "",
+    "features": [
+        "External Flash",
+        "JST-SH",
+        "USB"
+    ],
+    "images": [
+        "sparkfun_micromod_samd51.jpg"
+    ],
+    "mcu": "samd51",
+    "product": "Sparkfun SAMD51 MicroMod",
+    "thumbnail": "",
+    "url": "https://www.sparkfun.com/products/16791",
+    "vendor": "Sparkfun"
+}

ports/samd/boards/SPARKFUN_SAMD51_MICROMOD/mpconfigboard.h

@@ -0,0 +1,15 @@
+#define MICROPY_HW_BOARD_NAME       "Sparkfun SAMD51 MicroMod"
+#define MICROPY_HW_MCU_NAME         "SAMD51J20A"
+
+#define MICROPY_HW_XOSC32K          (1)
+
+// There seems to be an inconsistency in the SAMD51 Thing bootloader in that
+// the bootloader magic address is at the end of a 192k RAM area, instead of
+// 256k. Since the SAMD51x20A has 256k RAM, the loader symbol is at that address
+// and so there is a fix here using the previous definition.
+#define DBL_TAP_ADDR_ALT    ((volatile uint32_t *)(HSRAM_ADDR + HSRAM_SIZE - 0x10000 - 4))
+
+// Enabling both two lines below will set the boot file system to
+// the board's external flash.
+#define MICROPY_HW_SPIFLASH         (1)
+#define MICROPY_HW_SPIFLASH_ID      (0)

ports/samd/boards/SPARKFUN_SAMD51_MICROMOD/mpconfigboard.mk

@@ -0,0 +1,8 @@
+MCU_SERIES = SAMD51
+CMSIS_MCU = SAMD51J20A
+LD_FILES = boards/samd51x20a.ld sections.ld
+TEXT0 = 0x4000
+
+# The ?='s allow overriding in mpconfigboard.mk.
+# MicroPython settings
+MICROPY_HW_CODESIZE ?= 1008K

ports/samd/boards/SPARKFUN_SAMD51_MICROMOD/pins.csv

@@ -0,0 +1,60 @@
+# Pin rows contain Pin number and pin name.
+# Pin rows start with PIN_
+# If the pin name is omitted, the pin number is added as name.
+# Empty lines and lines not starting with PIN_ are ignored
+
+PIN_PA02,A0_DAC
+PIN_PA04,MOSI
+PIN_PA05,SCK
+PIN_PA06,MISO
+PIN_PA07,CS
+
+PIN_PA08,FLASH_SCK
+PIN_PA09,FLASH_MOSI
+PIN_PA10,FLASH_MISO
+PIN_PA11,FLASH_CS
+PIN_PA12,SCL1_TX2
+PIN_PA13,SDA1_RX2
+PIN_PA14,D10
+PIN_PA15,D11
+
+PIN_PA16,SCL
+PIN_PA17,SDA
+PIN_PA18,I2C_INT
+PIN_PA19,3V3_EN
+PIN_PA20,I2S_FS
+PIN_PA21,I2S_SDO
+PIN_PA22,I2S_SDI
+PIN_PA23,D13
+
+PIN_PA24,USB_DM
+PIN_PA25,USB_DP
+PIN_PA27,HOST_ENABLE
+
+PIN_PB00,A1
+PIN_PB01,A2_PWM0
+PIN_PB02,A3_PWM1
+PIN_PB03,A4
+PIN_PB04,D0
+PIN_PB05,D1
+PIN_PB06,D2_G0
+PIN_PB07,D3_G1
+
+PIN_PB08,D4_G2
+PIN_PB09,D5_G3
+PIN_PB10,D6_G4
+PIN_PB11,D7_G5
+PIN_PB12,D8_G6
+PIN_PB13,D9_G7
+PIN_PB14,CAN_TX
+PIN_PB15,CAN_RX
+
+PIN_PB16,I2S_CLK
+PIN_PB17,I2S_MCLK
+PIN_PB22,WP
+PIN_PB23,HOLD
+PIN_PB30,RXI
+PIN_PB31,TXO
+
+PIN_PA30,SWCLK
+PIN_PA31,SWDIO