SAMD20: Move serial console back to SERCOM4

configs/samd20-xplained/Kconfig

@@ -51,5 +51,26 @@ config SAMD20_XPLAINED_OLED1MODULE_EXT2
 endchoice
 endif
 
+if USART4_SERIAL_CONSOLE
+choice
+	prompt "USART 4 Connection"
+	default SAMD20_XPLAINED_USART4_EXT3
+
+config SAMD20_XPLAINED_USART4_EXT1
+	bool "EXT1"
+	depends on !SAMD20_XPLAINED_OLED1MODULE_EXT1 && !SAMD20_XPLAINED_IOMODULE_EXT1
+	---help---
+		Select this option if the serial console is on SERCOM4 connected via
+		EXT1.  The RX will be on PB9 and TX signal will be on PB8.
+
+config SAMD20_XPLAINED_USART4_EXT3
+	bool "EXT3"
+	---help---
+		Select this option if the serial console is on SERCOM4 connect via
+		EXT3.  The RX will be on PB13 and TX signal will be on PB12.
+
+endchoice
+endif
+
 endmenu
 endif

configs/samd20-xplained/include/board.h

@@ -198,7 +198,7 @@
 
 /* DFLL closed loop mode configuration */
 
-#define BOARD_DFLL_GCLKGEN         GCLK_CLKCTRL_GEN1
+#define BOARD_DFLL_SRCGCLKGEN         GCLK_CLKCTRL_GEN1
 #define BOARD_DFLL_MULTIPLIER         6
 #define BOARD_DFLL_QUICKLOCK          1
 #define BOARD_DFLL_TRACKAFTERFINELOCK 1
@@ -340,8 +340,45 @@
 #define BOARD_FLASH_WAITSTATES       0
 
 /* SERCOM definitions ***************************************************************/
+/* SERCOM4 is available on connectors EXT1 and EXT3
+ *
+ *   PIN   EXT1  EXT3  GPIO  Function
+ *   ----  ---- ------ -----------
+ *    13   PB09   PB13 SERCOM4 / USART RX
+ *    14   PB08   PB12 SERCOM4 / USART TX
+ *    19   19          GND
+ *    20   20          VCC
+ *
+ * If you have a TTL to RS-232 converter then this is the most convenient
+ * serial console to use.  It is the default in all of these configurations.
+ */
 
-/* EDBG/CDC USART on SERCOM3 */
+#define BOARD_SERCOM4_GCLKGEN        GCLK_CLKCTRL_GEN0
+
+#if defined(CONFIG_SAMD20_XPLAINED_USART4_EXT1)
+#  define BOARD_SERCOM4_MUXCONFIG    (USART_CTRLA_RXPAD1 | USART_CTRLA_TXPAD0)
+#  define BOARD_SERCOM4_PINMAP_PAD0  PORT_SERCOM4_PAD0_3
+#  define BOARD_SERCOM4_PINMAP_PAD1  PORT_SERCOM4_PAD1_3
+#  define BOARD_SERCOM4_PINMAP_PAD2  0
+#  define BOARD_SERCOM4_PINMAP_PAD3  0
+#else /* if defined(CONFIG_SAMD20_XPLAINED_USART4_EXT3) */
+#  define BOARD_SERCOM4_MUXCONFIG    (USART_CTRLA_RXPAD1 | USART_CTRLA_TXPAD0)
+#  define BOARD_SERCOM4_PINMAP_PAD0  PORT_SERCOM4_PAD0_1
+#  define BOARD_SERCOM4_PINMAP_PAD1  PORT_SERCOM4_PAD1_1
+#  define BOARD_SERCOM4_PINMAP_PAD2  0
+#  define BOARD_SERCOM4_PINMAP_PAD3  0
+#endif
+
+#define BOARD_SERCOM4_FREQUENCY      BOARD_GCLK0_FREQUENCY
+
+/* The SAMD20 Xplained Pro contains an Embedded Debugger (EDBG) that can be
+ * used to program and debug the ATSAMD20J18A using Serial Wire Debug (SWD).
+ * The Embedded debugger also include a Virtual Com port interface over
+ * SERCOM3.  Virtual COM port connections:
+ *
+ *   PA24 SERCOM3 / USART TXD
+ *   PA25 SERCOM3 / USART RXD
+ */
 
 #define BOARD_SERCOM3_GCLKGEN        GCLK_CLKCTRL_GEN0
 #define BOARD_SERCOM3_MUXCONFIG      (USART_CTRLA_RXPAD3 | USART_CTRLA_TXPAD2)

configs/samd20-xplained/nsh/defconfig

@@ -153,7 +153,7 @@ CONFIG_SAMD_HAVE_TC7=y
 # CONFIG_SAMD_SERCOM1 is not set
 # CONFIG_SAMD_SERCOM2 is not set
 CONFIG_SAMD_SERCOM3=y
-# CONFIG_SAMD_SERCOM4 is not set
+CONFIG_SAMD_SERCOM4=y
 # CONFIG_SAMD_SERCOM5 is not set
 # CONFIG_SAMD_TC0 is not set
 # CONFIG_SAMD_TC1 is not set
@@ -170,6 +170,9 @@ CONFIG_SAMD_SERCOM3=y
 # CONFIG_SAMD_SERCOM3_ISI2C is not set
 # CONFIG_SAMD_SERCOM3_ISSPI is not set
 CONFIG_SAMD_SERCOM3_ISUSART=y
+# CONFIG_SAMD_SERCOM4_ISI2C is not set
+# CONFIG_SAMD_SERCOM4_ISSPI is not set
+CONFIG_SAMD_SERCOM4_ISUSART=y
 
 #
 # Architecture Options
@@ -245,6 +248,8 @@ CONFIG_NSH_MMCSDMINOR=0
 #
 # CONFIG_SAMD20_XPLAINED_IOMODULE is not set
 # CONFIG_SAMD20_XPLAINED_OLED1MODULE is not set
+# CONFIG_SAMD20_XPLAINED_USART4_EXT1 is not set
+CONFIG_SAMD20_XPLAINED_USART4_EXT3=y
 
 #
 # RTOS Features
@@ -344,14 +349,17 @@ CONFIG_SERIAL=y
 # CONFIG_DEV_LOWCONSOLE is not set
 # CONFIG_16550_UART is not set
 CONFIG_ARCH_HAVE_USART3=y
+CONFIG_ARCH_HAVE_USART4=y
 
 #
 # USART Configuration
 #
 CONFIG_USART3_ISUART=y
+CONFIG_USART4_ISUART=y
 CONFIG_MCU_SERIAL=y
 CONFIG_STANDARD_SERIAL=y
-CONFIG_USART3_SERIAL_CONSOLE=y
+# CONFIG_USART3_SERIAL_CONSOLE is not set
+CONFIG_USART4_SERIAL_CONSOLE=y
 # CONFIG_NO_SERIAL_CONSOLE is not set
 
 #
@@ -365,6 +373,18 @@ CONFIG_USART3_PARITY=0
 CONFIG_USART3_2STOP=0
 # CONFIG_USART3_IFLOWCONTROL is not set
 # CONFIG_USART3_OFLOWCONTROL is not set
+
+#
+# USART4 Configuration
+#
+CONFIG_USART4_RXBUFSIZE=64
+CONFIG_USART4_TXBUFSIZE=64
+CONFIG_USART4_BAUD=9600
+CONFIG_USART4_BITS=8
+CONFIG_USART4_PARITY=0
+CONFIG_USART4_2STOP=0
+# CONFIG_USART4_IFLOWCONTROL is not set
+# CONFIG_USART4_OFLOWCONTROL is not set
 # CONFIG_SERIAL_IFLOWCONTROL is not set
 # CONFIG_SERIAL_OFLOWCONTROL is not set
 # CONFIG_USBDEV is not set