79 lines
3.2 KiB
Markdown
79 lines
3.2 KiB
Markdown
Mboot - MicroPython boot loader
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===============================
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Mboot is a custom bootloader for STM32 MCUs, and currently supports the
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STM32F4xx and STM32F7xx families. It can provide a standard USB DFU interface
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on either the FS or HS peripherals, as well as a sophisticated, custom I2C
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interface. It fits in 16k of flash space.
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How to use
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----------
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1. Configure your board to use a boot loader by editing the mpconfigboard.mk
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and mpconfigboard.h files. For example, for an F767 be sure to have these
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lines in mpconfigboard.mk:
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LD_FILES = boards/stm32f767.ld boards/common_bl.ld
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TEXT0_ADDR = 0x08008000
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And this in mpconfigboard.h (recommended to put at the end of the file):
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// Bootloader configuration
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#define MBOOT_I2C_PERIPH_ID 1
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#define MBOOT_I2C_SCL (pin_B8)
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#define MBOOT_I2C_SDA (pin_B9)
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#define MBOOT_I2C_ALTFUNC (4)
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To configure a pin to force entry into the boot loader the following
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options can be used (with example configuration):
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#define MBOOT_BOOTPIN_PIN (pin_A0)
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#define MBOOT_BOOTPIN_PULL (MP_HAL_PIN_PULL_UP)
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#define MBOOT_BOOTPIN_ACTIVE (0)
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Mboot supports programming external SPI flash via the DFU and I2C
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interfaces. SPI flash will be mapped to an address range. To
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configure it use the following options (edit as needed):
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#define MBOOT_SPIFLASH_ADDR (0x80000000)
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#define MBOOT_SPIFLASH_BYTE_SIZE (2 * 1024 * 1024)
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#define MBOOT_SPIFLASH_LAYOUT "/0x80000000/64*32Kg"
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#define MBOOT_SPIFLASH_ERASE_BLOCKS_PER_PAGE (32 / 4)
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#define MBOOT_SPIFLASH_SPIFLASH (&spi_bdev.spiflash)
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#define MBOOT_SPIFLASH_CONFIG (&spiflash_config)
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This assumes that the board declares and defines the relevant SPI flash
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configuration structs, eg in the board-specific bdev.c file. The
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`MBOOT_SPIFLASH2_LAYOUT` string will be seen by the USB DFU utility and
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must describe the SPI flash layout. Note that the number of pages in
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this layout description (the `64` above) cannot be larger than 99 (it
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must fit in two digits) so the reported page size (the `32Kg` above)
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must be made large enough so the number of pages fits in two digits.
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Alternatively the layout can specify multiple sections like
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`32*16Kg,32*16Kg`, in which case `MBOOT_SPIFLASH_ERASE_BLOCKS_PER_PAGE`
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must be changed to `16 / 4` to match tho `16Kg` value.
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Mboot supports up to two external SPI flash devices. To configure the
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second one use the same configuration names as above but with
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`SPIFLASH2`, ie `MBOOT_SPIFLASH2_ADDR` etc.
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2. Build the board's main application firmware as usual.
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3. Build mboot via:
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$ cd mboot
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$ make BOARD=<board-id>
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That should produce a DFU file for mboot. It can be deployed using
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USB DFU programming via (it will be placed at location 0x08000000):
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$ make BOARD=<board-id> deploy
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4. Reset the board while holding USR until all 3 LEDs are lit (the 4th option in
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the cycle) and then release USR. LED0 will then blink once per second to
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indicate that it's in mboot
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5. Use either USB DFU or I2C to download firmware. The script mboot.py shows how
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to communicate with the I2C boot loader interface. It should be run on a
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pyboard connected via I2C to the target board.
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