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--- project:arm_debugging:start [2019/12/22 16:26] – [Example: Unbricking (restoring) Proxmark bootloader] abyssal
+++ project:arm_debugging:start [2020/07/25 12:26] – ARM ITM trace HOWTO abyssal
@@ Line 313: / Line 313: @@
 {{ :project:proxmark-jlink.jpg?800 | }}
+===== SystemView for J-link - visualization of interrupts or other functions =====
+There is an instrumentation possible with changes to code to show how your functions and interrupts behave - [[https://wiki.segger.com/Use_SystemView_without_RTOS | sample code]]
+Here is an example showing "tail chaining" of interrupts where interrupts are behind one another, and also "late arriving", where Systick interrupts USB interrupt (marked as IST #93 starting at position 2195):
+{{:project:arm_debugging:systemview_20200318_113539.png?800|}}
+If you add extra functions, it may measure your functions as well:
+{{:project:arm_debugging:systemview_20200318_100652.png?800|}}
+As a side note, ST-link on STM32 discovery boards can be reflashed to JLink (works only on discovery boards, not on separate ST-links).
+===== ARM ETM trace - recording executed instructions =====
+ARM processors (Cortex M1+ and others) have built-in a nifty feature that you can record all instructions executed. This requires quite costly hardware (expect 2000 EUR price - JTrace, Lauterbach and uLink), but it can be handy in debugging DMA and interrupts.
+An example ETM trace:
+{{:project:arm_debugging:ozone_error_shutdown_highlighted.png?800|}}
+===== ARM ITM trace - recording samples of executed instructions, interrupts =====
+You can get code profile like this with ITM (screenshow from ''orbtop''):
+{{:project:arm_debugging:orbtop_trezor_lots_of_segwit_inputs.png|}}
+To get this working, [[https://github.com/hiviah/ITM-howto-JLink-STLink|follow this howto]]. It shows steps to be used with JLink/JTrace or STLink to get it moving.
 ====== Flyswatter connected to Proxmark ======