AM2634: Correct procedure to halt R5FSS1 during runtime

Hi Volodymyr,

Since the two cores are running independently; I do not think there is a way you can stop the R5F_1_0 from R5F_0_0. The correct way is to use the IPC to sync between two cores. If R5F_0_0 wants to stop/restart the R5F_1_0, simply send an IPC message/notification. The R5F_1_0 will do whatever R5F_0_0 ask it to do.

Please refer to the IPC example: ipc_notify_echo_am263x-cc_system_freertos_nortos and

AM263x MCU+ SDK: Understanding inter-processor communication (IPC)

for details.

Best regards,

Ming

Ming Wei

Thank you for reply but question was not about IPC. I have IPC up and running. I do not see explicit API to halt the core in the SDK.

My question is what actions should I perform to halt the core correctly ?

Hi Ming

I assume that if SDK has unhalt API SOC_rcmCoreR5FUnhalt() so should be a reversed one to halt core.

My goal is to stop execution on satellite core and achieve 0 consumption - I am not sure I can get same result with while(1) loop

Or bring back satellite core to initial state - as I understand bootloader does some actions to prepare multi core application to run on different cores or I missed something ?

Hi Ming

I did try this approach but without any effect. Moreover the AM263x TRM doc says that this register must be written only once.

Anyway for now I decided to stay on solution that relies on IPC message that informs specific core to halt and sequence of commands:

  HwiP_disable();
_isb();
_dsb();
while(TRUE) __asm__ volatile ("wfi");

WFI command stays inside while loop to prevent escaping during debug activities.

I have marked your suggestion above as a solution. Please feel free to comment if you find any issues in my implementation.

Thank you 

Hi Aakash

Thank you for advice. It really helped to write the register but I didn't notice any additional effect ( at least while debugger is connected ).

My assumption is to get core state in debugger - Suspended, after the core is halted. Instead of this I see core Running on while(TRUE) __asm__ volatile ("wfi"); statement.

The next question here is can I reuse satellite core RAM space while core is halted the way like above ?

Thank you 

Hi Ming

You missed my point above - my goal is to halt the satellite core correctly and reuse its RAM area. I am disabling interrupts before getting into WFI loop ( code snippet above )

Thank you