A Method for Absolute Memory Address Location in MCUs

Follow+Star Public Account Number, don’t miss out on exciting contentSource | Renesas Embedded EncyclopediaIn a previous article titled “How to Add Version Information to MCU Projects?” we used absolute addresses:

#define VERINFO_ADDR_BASE   (0x0800FF00) // Address for storing FLASH
const char Software_Ver[] __attribute__((at(VERINFO_ADDR_BASE + 0x00)))  = "Software: 1.0.0";
const char Compiler_Date[] __attribute__((at(VERINFO_ADDR_BASE + 0x40))) = "Date: " __DATE__;
const char Compiler_Time[] __attribute__((at(VERINFO_ADDR_BASE + 0x60))) = "Time: " __TIME__;

Today, I will share another method for absolute address location in Flash on Renesas e² studio.

The main approach is to modify the .ld script file using the official Renesas compiler tool e² studio, allocating a small section in Flash, and then implementing it through __attribute__.

The specific steps are as follows

1

First, allocate a section in Flash and modify the .ld file in e² studio. The project path is shown in the image below

2

In the fsp.ld file, under the memory options, add a new partition, directly specifying the starting address and length.

3

In fsp.ld, under text editing, initialize my_code (!rx), and remove the “!”

4

Edit my_code as shown below

The text editor will automatically create the following code:

5

To avoid potential issues, it is best to modify the Flash address space, as at this point, my_code is encapsulated in the Flash area, requiring modification of the Flash area address.

First, copy memory_regions.ld and rename it in the same directory, then include the newly copied file in the fSP.ld file’s text editor:

Next, we need to modify the Flash space in memory_regions_my.ld

Similarly, we can set the starting address and length of my_code here, directly replacing the starting address and length alias in the newly created partition from step 2.

6

In the main function variable declaration, add the following code

const char buff[16] __attribute__((section(“.my_code “))) = {“1234567890abcdef”};

The length of buff must match the partition size, otherwise an error will occur.

Build needs to use release.

7

After compilation, check as follows:

I recommend using e² studio help contents.

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