Moved the old firmware for STM32L011 to fw_old and migrated the firmware to STM32L031 in fw. I2C and TIM21 seem functional. USART2 is receiving correctly, but the modbus test is not receiving messages.

fw_old/Debug/makefile

@@ -0,0 +1,100 @@
+################################################################################
+# Automatically-generated file. Do not edit!
+# Toolchain: GNU Tools for STM32 (9-2020-q2-update)
+################################################################################
+
+-include ../makefile.init
+
+RM := rm -rf
+
+# All of the sources participating in the build are defined here
+-include sources.mk
+-include Drivers/STM32L0xx_HAL_Driver/Src/subdir.mk
+-include Core/Startup/subdir.mk
+-include Core/Src/subdir.mk
+-include subdir.mk
+-include objects.mk
+
+ifneq ($(MAKECMDGOALS),clean)
+ifneq ($(strip $(S_DEPS)),)
+-include $(S_DEPS)
+endif
+ifneq ($(strip $(S_UPPER_DEPS)),)
+-include $(S_UPPER_DEPS)
+endif
+ifneq ($(strip $(C_DEPS)),)
+-include $(C_DEPS)
+endif
+endif
+
+-include ../makefile.defs
+
+OPTIONAL_TOOL_DEPS := \
+$(wildcard ../makefile.defs) \
+$(wildcard ../makefile.init) \
+$(wildcard ../makefile.targets) \
+
+
+BUILD_ARTIFACT_NAME := iaq_wired_sensor
+BUILD_ARTIFACT_EXTENSION := elf
+BUILD_ARTIFACT_PREFIX :=
+BUILD_ARTIFACT := $(BUILD_ARTIFACT_PREFIX)$(BUILD_ARTIFACT_NAME)$(if $(BUILD_ARTIFACT_EXTENSION),.$(BUILD_ARTIFACT_EXTENSION),)
+
+# Add inputs and outputs from these tool invocations to the build variables 
+EXECUTABLES += \
+iaq_wired_sensor.elf \
+
+SIZE_OUTPUT += \
+default.size.stdout \
+
+OBJDUMP_LIST += \
+iaq_wired_sensor.list \
+
+OBJCOPY_BIN += \
+iaq_wired_sensor.bin \
+
+
+# All Target
+all: main-build
+
+# Main-build Target
+main-build: iaq_wired_sensor.elf secondary-outputs
+
+# Tool invocations
+iaq_wired_sensor.elf: $(OBJS) $(USER_OBJS) /home/mrs/Personal/HDIoT/Smart_Household/iaq_wired_sensor/fw/STM32L011F4UX_FLASH.ld makefile objects.list $(OPTIONAL_TOOL_DEPS)
+	arm-none-eabi-gcc -o "iaq_wired_sensor.elf" @"objects.list" $(USER_OBJS) $(LIBS) -mcpu=cortex-m0plus -T"/home/mrs/Personal/HDIoT/Smart_Household/iaq_wired_sensor/fw/STM32L011F4UX_FLASH.ld" --specs=nosys.specs -Wl,-Map="iaq_wired_sensor.map" -Wl,--gc-sections -static --specs=nano.specs -mfloat-abi=soft -mthumb -Wl,--start-group -lc -lm -Wl,--end-group
+	@echo 'Finished building target: $@'
+	@echo ' '
+
+default.size.stdout: $(EXECUTABLES) makefile objects.list $(OPTIONAL_TOOL_DEPS)
+	arm-none-eabi-size  $(EXECUTABLES)
+	@echo 'Finished building: $@'
+	@echo ' '
+
+iaq_wired_sensor.list: $(EXECUTABLES) makefile objects.list $(OPTIONAL_TOOL_DEPS)
+	arm-none-eabi-objdump -h -S $(EXECUTABLES) > "iaq_wired_sensor.list"
+	@echo 'Finished building: $@'
+	@echo ' '
+
+iaq_wired_sensor.bin: $(EXECUTABLES) makefile objects.list $(OPTIONAL_TOOL_DEPS)
+	arm-none-eabi-objcopy  -O binary $(EXECUTABLES) "iaq_wired_sensor.bin"
+	@echo 'Finished building: $@'
+	@echo ' '
+
+# Other Targets
+clean:
+	-$(RM) $(SIZE_OUTPUT)$(OBJDUMP_LIST)$(EXECUTABLES)$(OBJS)$(S_DEPS)$(S_UPPER_DEPS)$(C_DEPS)$(OBJCOPY_BIN) iaq_wired_sensor.elf
+	-@echo ' '
+
+secondary-outputs: $(SIZE_OUTPUT) $(OBJDUMP_LIST) $(OBJCOPY_BIN)
+
+fail-specified-linker-script-missing:
+	@echo 'Error: Cannot find the specified linker script. Check the linker settings in the build configuration.'
+	@exit 2
+
+warn-no-linker-script-specified:
+	@echo 'Warning: No linker script specified. Check the linker settings in the build configuration.'
+
+.PHONY: all clean dependents fail-specified-linker-script-missing warn-no-linker-script-specified
+
+-include ../makefile.targets