STM8S datasheet(31/467 Pages) STMICROELECTRONICS

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RM0016

Memory and register map

3.1.2

Stack handling

Default stack model

The stack of the STM8S and STM8AF microcontrollers is implemented in the user RAM

area. The default stack model is shown in Figure 4.

Figure 4. Default stack model

1. The stack roll-over limit is not implemented on all devices. Refer to the datasheets for detailed information.

Stack pointer initialization value

This is the default value of the stack pointer. The user must take care to initialize this pointer.

Correct loading of this pointer is usually performed by the initialization code generated by

the development tools (linker file). In the default stack model this pointer is initialized to the

RAM end address.

Stack roll-over limit

In some devices, a stack roll-over limit is implemented at a fixed address. If the stack pointer

is decreased below the stack roll-over limit, using a push operation or during context saving

for subroutines or interrupt routines, it is reset to the RAM end address. The stack pointer

does not roll over if stack pointer arithmetic is used.

Such behavior of the stack pointer is of particular importance when developing software on

a device with a different memory configuration than the target device.

ai15055v2

Default stack model

End address

Stack roll-over limit (1)

Stack pointer initialization value

Start address

RAM

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