Device firmware upgrade support

UM0463

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Device firmware upgrade support

The library provides the support for the IAP which is used to change the application code

(present in sector 1 and sector 2) through the USB without disturbing the code of sector 0.

The Boot loader (USB + DFU) code of the library is placed in the sector 0. The user has to

take care that his code is always placed in sector 1 and sector 2 and the code in sector 0

should not be disturbed. Use only those pragmas which are used in user code file or new

defined pragmas. Don't use pragmas of bootloader. Refer to the lkf file for pragmas of each

sector.

To upgrade the firmware the user has to go to DFU mode and after upgrading he has to

return to the application mode. There can be two possible scenarios to go to DFU mode:

1.

Composite mode: DFU Detach command is issued on the DFU interface to jump from

application mode to DFU mode

2.

Noncomposite mode: In this mode the user has to enter the DFU mode by means of

checking the hardware switch after reset (e.g. Check the port status, if the pin level is

low then boot in DFU mode, else go to the application mode). The current code is using

PF3. If it's LOW, DFU mode is entered, otherwise it will boot in an application mode.

Firmware Upgrade: In the DFU mode, the user can upgrade the firmware through the PC

GUI. For upgrading the firmware the user first needs to convert .s19 file into .dfu file through

the GUI. Once converted, this dfu file will be used by the GUI to upgrade the firmware. For

changing the code, the flash of microcontroller needs 12 V during erasing and writing. The

supply for this 12 V should be available on the board (e.g. using charge pump ST662A).

Caution:

12 V should be supplied to the VPP pin of the microcontroller only during erasing or writing

the flash.