Fujitsu MB91460 SERIES Application Note - Page 7

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Note: For all other devices, including "others" the section SECURITY_VECTORS is located

from 0x14:8000 – 0x14:800F.

Example:

The security feature of target controller should be disabled.

#set

BOOT_FLASH_SEC

2.3 Stack Type and Stack Size (STACKUSE, ...)

2.3.1 STACKUSE

The setting STACKUSE specifies the stack type that is configured, when the application

main()-function is called. The devices of MB91460 Series provide two different types of

stack: system stack and user stack. The application can use either system stack only or it

can use both system stack and user stack.

System stack is always used for interrupt function. It is automatically selected, if hardware

interrupts are executed or if software interrupts are called. All stack operation of interrupt

handlers will work with the system stack.

Outside of interrupt handlers the pre-selected stack type is used. This is either user stack

(option USRSTACK) or system stack (option SYSSTACK). If SYSSTACK is set, only the

system stack area has to be prepared. All operation will work on the same stack. The

necessary safety margin has to be reserved for one stack only. SYSSTACK should be used,

if the necessary RAM consumption for stack has to be low. If USRSTACK is set, both

system stack and user stack have to be prepared. The necessary safety margin has to be

provided twice. USRSTACK should be used, if separated stack areas are necessary for

management reasons. This might be the case with schedulers, operating systems or other

applications.

Available settings for STACKUSE:

- USRSTACK

- SYSSTACK

Example:

The user stack should be used outside of interrupt handlers. This requires the setting.

#set

STACKUSE

2.3.2 STACK_RESERVE, STACK_SYS_SIZE, STACK_USR_SIZE

These settings specify the amount of bytes to be reserved for stacks. This value has to cover

all:

- parameters passed over stack

- return addresses for function calls

- local variables (except static)

- temporary data due to compiler optimization

- interrupt context on stacks

- safety margin

For estimating necessary stack size the compiler offers the "-INF stack" option. With it the

compiler generates stack information files (extension "stk"), which list the number of bytes

necessary to execute each function. These stack information files are already available for

Start91460.asm

Chapter 2 Settings of the Start91460.asm

OFF

; <<< BOOT and Flash Security Vector

USRSTACK

- 7 -

; <<< set active stack

MCU-AN-300021-E-V10