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2.3 TRANSITION BETWEEN USB AND APPLICATION

The transition between the application firmware and the DFU firmware is made only through

an MCU reset. A software reset is performed using the Watchdog control register when the

USB cable is detected.

The transition between the DFU firmware and the application firmware is made through a

“Jump Table”. In fact, the DFU firmware only needs to know the address of the application

main routine. This address is saved in the last bytes of Sector 1.

2.4 RAM

As the execution of the firmware in Sector 0 and Sectors 1 & 2 always starts after a MCU

Reset, we have no RAM overlapping problem. Furthermore, as it is a non-USB application,

there none of the USB Library functions are called by the main application. So, there is also no

problem of parameter passing. This simplifies the RAM management a lot.