LP-AM243: Changing MCU clock speed

Hi Jesse,

Here is how to change the Clock frequency for AM243x. In C:\ti\mcu_plus_sdk_am243x_08_02_00_31\source\drivers\bootloader\soc\am64x_am243x\bootloader_soc.c, there is a structure gCoreBootInfo. You can change the .defaultClockHz for any core ("r5f0-0", "r5f0-1", "r5f1-0" or "r5f1-1" even "m4f0-0").

After change the gCoreBootInfo, you will need to re-build the sbl_null and then flash it into the OSPI. Refer to AM243x MCU+ SDK: EVM Setup (ti.com) for details.

Best regards,

Ming

Hi Ming,

When you say re-build the sbl_null, do we rebuild the sbl_null project in ccs with the edited bootloader_soc.c file included the project?

Here are the steps I'm currently following:

1. Import sbl_null_am243x-lp... project from SDK into CCS
2. Import bootloader_soc.c into project and modify clock frequency
3. Build project
4. Use *.tiimage from rebuilt project to replace sbl_null.release.tiimage specified by default_sbl_null.cfg
5. Follow steps here to flash the updated sbl_null

Are these steps correct to preserve clock change? Does it look like I'm missing anything?

Best regards,

Jesse

Hi Jesses,

The most steps you did are correct. The only thing you missed is the re-build of the drivers library after you change the bootloader_soc.c. You do not need to import the bootloader_soc.c into your CCS project

cd C:\ti\mcu_plus_sdk_am243x_08_02_00_31

gamke -s -f makefile.am243x drivers_r5f.ti-arm-clang_clean

gamke -s -f makefile.am243x drivers_r5f.ti-arm-clang

then re-build the sbl_null project.

Best regards,

Ming

Hi Ming,

I followed the steps above, but when I run my application (in debug mode in CCS), I still see that the clock is initialized to 800 MHz when I check the CPU frequency using Bootloader_socCpuGetClock().

However, I have seen that if I call Bootloader_socCpuSetClock() at the beginning of my application code to set the CPU frequency to the desired frequency (for example 200 MHz) and then read the CPU frequency using Bootloader_socCpuGetClock(), I see that the clock has been updated to 200 MHz.

Is using Bootloader_socCpuSetClock() in my application code like this a valid way to update or change the CPU clock frequency?

Best regards,

Jesse