Software description

AN3265

16/19

Doc ID 17860 Rev 1

2.3.5

Saving SystemState in data EEPROM

To demonstrate how to use the data EEPROM for saving data, the SystemState global

variable is saved and then read back from memory.

This step is not mandatory since there are several solutions to keep this variable unchanged

during reset. The solution depends on the compiler.

Raisonance compiler

SystemState must be declared as global since global variables are created either in the

Zero Page or in the RAM Data segments and are consequently not re-initialized at reset.

Cosmic compiler

Cosmic compiler re-initializes global variables at startup. The steps required to save the

value of SystemState in data EEPROM:

1.

Declare the global variable with the following example syntax

#pragma section [my_sec]

u8 SystemState;

#pragma section []

2.

Then two solutions are possible:

–

Either create the my_sec section in the Zero Page with the extension ‘-ib’ that

prevents Cosmic compiler from re-initializing its content at reset. This can be done

in the STVD Project > Settings > Linker tab > Category: Input menu (see

Figure 7).

–

Or directly modify the project linker file to perform the same operation. It is

mandatory to remove the Auto option in STVD linker tab (see Figure 7). To do this,

open the file CSS_WDG_Robustness.lkf located in the STVD/Cosmic/Debug

folder of the Cosmic project and modify it as follows.

# Segment Zero Page:

+seg .bsct -b 0x0 -m 0x100 -n .bsct

+seg .ubsct -a .bsct -n .ubsct

+seg .bit -a .ubsct -n .bit -id

+seg .share -a .bit -n .share -is

+seg .my_sec -a .share -n .my_sec –ib

For more details, refer to the Cosmic user manual available in the Cosmic

installation directory