Basic MAC Out-of-Tree Example

This example demonstrates how to setup an out-of-tree project that uses a custom board for both Basic MAC and Basic Loader.

The actual firmware is simply a copy of the ex-join example that is part of Basic MAC.

Preparation

At the time of writing, there is a small bug that prevent out-of-tree builds for Basic Loader and one that prevents out-of-tree builds with custom boards for Basic MAC projects.

Apply the supplied patches, basicloader.patch and basicmac.patch to the respective repositories until such time that these bugs are fixed upstream.

Bootloader

Creating a Basic Loader variant for a new board of an already supported MCU is very simple. Simply create a Makefile in a new directory and set the TOPDIR variable to the Basic Loader directory, specify the flavor and MCU:

bootloader/Makefile

TOPDIR  := /work/current/basicmac/basicloader
FLAVOR  := stm32lx
MCU     := STM32L073Z

include $(TOPDIR)/build/boards/main.mk

# The bootloader (optionally) uses an LED to blink out diagnostics information
# after an exception occurs, and during installation of an update.
CDEFS   += BOOT_LED_GPIO="GPIO('A',7,0)"

Then, you can simply type make in that directory to build the bootloader.hex file.

Firmware

To build a Basic MAC firmware project out-of-tree, you need to set the TOPDIR variable to the Basic MAC directory in the Makefile and include the $(TOPDIR)/projects/project.gmk file:

firmware/Makefile

TOPDIR := /work/current/basicmac

...

include $(TOPDIR)/projects/projects.gmk

Further, to build for a custom board, which we'll call myowndevice in this example, you'll need to create a family makefile that will set up the build environment for this target:

firmware/target.mk

ifeq (myowndevice,$(TARGET))
    MCU         := stm32l0
    LD_SCRIPTS  += $(BL)/src/arm/stm32lx/ld/STM32L0xxZ.ld
    DEFS        += -DSTM32L0 -DSTM32L073xx
    DEFS        += -DCFG_myowndevice_board
    DEFS        += -DBRD_IMPL_INC='"$(CURDIR)/brd_myowndevice.h"'
endif

As you can see, this setup calls for a custom board implementation header file, brd_myowndevice.h, which will be included in the build. This file contains macro definitions for radio type, peripherals, and GPIOs used:

firmware/brd_myowndevice.h

#if defined(CFG_myowndevice_board)

// Use the SX1276
#define BRD_sx1276_radio

// GPIOs connected to the SX1276
#define GPIO_RST	BRD_GPIO(PORT_B, 10)       // PB10
#define GPIO_DIO0	BRD_GPIO(PORT_B, 11)       // PB11
#define GPIO_DIO1	BRD_GPIO(PORT_C, 13)       // PC13
#define GPIO_DIO2	BRD_GPIO(PORT_B, 9)        // PB9
#define GPIO_DIO3	BRD_GPIO(PORT_B, 4)        // PB4, not used by stack
#define GPIO_DIO4	BRD_GPIO(PORT_B, 3)        // PB3, not used by stack
#define GPIO_DIO5	BRD_GPIO(PORT_A, 15)       // PA15, not used by stack

// SPI bus connection to the SX1276
#define BRD_RADIO_SPI	2                          // SPI2
#define GPIO_NSS	BRD_GPIO(PORT_B, 12)       // PB12
#define GPIO_SCK	BRD_GPIO_AF(PORT_B, 13, 0) // PB13, alternate function 0
#define GPIO_MISO	BRD_GPIO_AF(PORT_B, 14, 0) // PB14, alternate function 0
#define GPIO_MOSI	BRD_GPIO_AF(PORT_B, 15, 0) // PB15, alternate function 0

// UART for debug output
#define BRD_DBG_UART	1                          // UART1
#define GPIO_DBG_TX	BRD_GPIO_AF(PORT_A, 9, 4)  // PA9, alternate function 4

#endif

Finally, the Makefile must set our custom target and add the custom family makefile to the list of family makefiles:

firmware/Makefile

TARGET := myowndevice

...

FAM_MAKEFILES += target.mk

And now, you are ready to type make!