stm32: add support for the STM32L031G6U6

GNUmakefile

@@ -837,6 +837,8 @@ ifneq ($(STM32), 0)
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=mksnanov3           examples/blinky1
 	@$(MD5SUM) test.hex
+	$(TINYGO) build -size short -o test.hex -target=stm32l0x1           examples/serial
+	@$(MD5SUM) test.hex
 endif
 	$(TINYGO) build -size short -o test.hex -target=atmega328pb         examples/blinkm
 	@$(MD5SUM) test.hex
@@ -907,7 +909,7 @@ endif
 	$(TINYGO) build -size short -o test.hex -target=hw-651              examples/machinetest
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=hw-651-s110v8       examples/machinetest
-	@$(MD5SUM) test.hex	
+	@$(MD5SUM) test.hex
 ifneq ($(WASM), 0)
 	$(TINYGO) build -size short -o wasm.wasm -target=wasm               examples/wasm/export
 	$(TINYGO) build -size short -o wasm.wasm -target=wasm               examples/wasm/main

src/machine/board_stm32l0x1.go

@@ -0,0 +1,18 @@
+//go:build stm32l0x1 && !nucleol031k6
+
+// This file is for the bare STM32L0x1 (not for any specific board that is based
+// on the STM32L0x1).
+
+package machine
+
+const (
+	I2C0_SCL_PIN = NoPin
+	I2C0_SDA_PIN = NoPin
+
+	UART_TX_PIN = NoPin
+	UART_RX_PIN = NoPin
+
+	SPI0_SDI_PIN = NoPin
+	SPI0_SDO_PIN = NoPin
+	SPI0_SCK_PIN = NoPin
+)

targets/stm32l031x6.ld

@@ -0,0 +1,10 @@
+
+MEMORY
+{
+  FLASH_TEXT (rx) : ORIGIN = 0x08000000, LENGTH = 32K
+  RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 8K
+}
+
+_stack_size = 2K;
+
+INCLUDE "targets/arm.ld"

targets/stm32l0x1.json

@@ -0,0 +1,18 @@
+{
+    "inherits": [
+        "cortex-m0plus"
+    ],
+    "build-tags": [
+        "stm32l031",
+        "stm32l0x1",
+        "stm32l0",
+        "stm32"
+    ],
+    "linkerscript": "targets/stm32l031x6.ld",
+    "extra-files": [
+        "src/device/stm32/stm32l0x1.s"
+    ],
+    "flash-method": "openocd",
+    "openocd-interface": "cmsis-dap",
+    "openocd-target": "stm32l0"
+}