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--- project:arm_debugging:start [2019/12/22 15:49] – [Example: Unbricking (restoring) Proxmark bootloader] abyssal
+++ project:arm_debugging:start [2020/03/18 21:02] – [J-link/JTrace] SystemView, STLink to JLink flash, ARM ETM tracing abyssal
@@ Line 303: / Line 303: @@
 This is happening mostly on cheap clones of proxmark3 Easy.
-To debug Proxmark on newer OpenOCD >= 0.10.0, you may set fast memory access:
+To debug Proxmark on newer OpenOCD >= 0.10.0, you may set fast memory access and fast DCC downloads:
 <code>
-openocd -c "adapter_khz 4000" -f interface/jlink.cfg -c "gdb_memory_map disable" -f target/at91sam7x256.cfg -c "init; arm7_9 fast_memory_access enable;"
+openocd -c "adapter_khz 4000" -f interface/jlink.cfg -c "gdb_memory_map disable" -f target/at91sam7x256.cfg -c "init; arm7_9 fast_memory_access enable; arm7_9 dcc_downloads enable"
 </code>
@@ 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|}}
 ====== Flyswatter connected to Proxmark ======