How to check the DAP is not closed properly

RE: How to check the DAP is not closed properly

Vidar Berg — Tue, 09 Nov 2021 12:01:32 GMT

Hello,

There does not appear to be a good way to programmatically detect whether the chip is in debug interface mode, unfortunately. You have the C_DEBUGEN bit in CoreDebug->DHCSR (link), but this register is only reset after a power-on reset (i.e. it will remain set after the debugger has exited debug mode).

I think your best option is to verify that your programming setup is exiting debug mode after programming as it is supposed to on a device that has not been encapsulated.

RE: How to check the DAP is not closed properly

Maverick2k — Tue, 02 Nov 2021 18:16:11 GMT

Hello,

Thank you for your reply. Unfortunately, the device is fully molded with no access to the power source, so also not for measuring. I can conduct wireless updates, but if there is no way to check if the DAP is activated and or disable it, there is no use.

If you find out more information internally let me know.

Thank you in advance.

RE: How to check the DAP is not closed properly

Vidar Berg — Mon, 01 Nov 2021 15:35:03 GMT

Hello,

If I recall correctly, it is only possible to power down the debug interface externally via the debug interface. I also do not think it is possible to check programmatically if the chip is in debug interface mode or not. But I will ask internally to confirm.

[quote user=""]What behavior is influenced when the DAP is activated? E.g. timers, sleep, etc?[/quote]

In debug interface mode, the system will keep certain resources needed for debugging active as stated here in the PS: Emulated System OFF mode. This will normally not have any affect on the functional behavior of your device, except for shorter wake up times for interrupts.

[quote user=""]Secondly, how can you make sure the DAP is deactivated, without a complete power cycle? Since a power cycle is not an option.[/quote]

Can you measure the current consumption? The "sleep" current in debug interface mode is around ~3 mA.

Best regards,

Vidar