DocID026482 Rev 1

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AN4515

Application Overview

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Figure 2. Batch Acquisition Mode use case

1.3.3

How to implement BAM

When the BAM is enabled, the Flash memory is switched off by setting the FMSSR and

FISSR bits in PWR_CR register. These bits cannot be set while executing the program from

Flash memory. This can be done through a specific routine executed from RAM (see

Figure 3, Figure 4 and Figure 5 for a description).

Three methods can be used to implement the BAM. Each approach depends on user

application:

•

Executing Interrupts from RAM

•

Executing Interrupts from Flash memory

•

Using events to wake up the CPU

Executing interrupts from RAM

This is the approach used in the application note use case (see Figure 3). The device is

woken up from Sleep by an interrupt. The user application has therefore to store the

required ISRs and the vector table in the RAM so that it is immediately executed from the

RAM when the interrupt occurs.