Use of DATA GROUP

I already generated ROM code and i would to use Eeprom memory to add some fucntionality but without any change of ROM code since it is already loaded. But when i add more than 1 local variable in my function the ROM code changed and cause problemes after link.

Thank you

Hi Daniel,

Split your Project into two.
One for your ROM and one for EEPROM.
After generating ROM-Project look the used resources in DATA, XDATA etc. These had to be excluded from EEPROM-Project.
And for using functions in EEPROM use adresstabel with entrypoints.

Chris

I am very confused. How can you extend the fuctionality of rom code without changing the rom?

One of the disgusting facts about the Keil software is that if you change the name of a variable (or add one) the whole DATA segment layout changes. Not using overlay is usually not an option. I sometimes work with software written by someone or another who uses variable names that are meaningless and in reforming such code I like to change the names and then compare the hex files to ensure that the namechange was the only change (I do make mistakes). This works fine for functions, but try it with a variable and booooooom, the whole hex file changes. As testing only guarantees the absence of KNOWN bugs, it takes an inordinate amount of time to verify what could be verified with a simple hex compare if the sequence of the variables were not shuffled.

It would make sense to order the variables by occurence rather than some random? order.

Happy hollidays,

Erik

Hi Jon,

Daniel wrote that he had ROM and EEPROM. And he want to add some functionnality in Eeprom:

So i understand he will change the content of EEPROM. Physical by exchange or by in circuit programming.

By writing/generating code with uvision he need to split his project. One for target ROM and one for target EEPROM.
And when he calls function in EEPROM the ROMcode need the locations of EEPROM function. And this can be done tables with function entry points.

This is what i have done in an project with Bootloader and reprogrammable Applikation.

Chris

If you want no sorted variables use NOSO (no sort) as directive for the Linker.
This is not documented but comes as info directly from Keil.

Chris

*<|:-), merry xmas

The NOSO (short for NOSORTSIZE) is documented on p316 in the current Linker manual (07.2000)

But this relates to the ordering of Segments - not variables.

If I understand what he originally posted: Some code in ROM, some in flash. Adding a variable using ONLY in flash changes the location of variables used in ROM AND flash.

Happy hollidays

Erik