[En-Nut-Discussion] NutOS (trunk) causes freeze

Uwe Bonnes bon at elektron.ikp.physik.tu-darmstadt.de
Thu Jul 19 10:54:43 CEST 2012

>>>>> "Rob" == Rob van Lieshout \(PragmaLab\) <Rob> writes:

    Rob> The thing that comes closest is the SysTick timer that is present
    Rob> in the LPC177x_8x MCU. But that one only contains one counter and
    Rob> resides on a different address then your recent CORTEX modification
    Rob> contains:

Systick is another story and already used...

    Rob> The addresses you use in your CORTEX modification (now: MCU_STM32
    Rob> modification) are in a reserved area of the LPC MCU. Might explain
    Rob> the freeze.....?

    Rob> Can you point me to the DWT description in the user manual? I have
    Rob> here the UM10470 (LPC178x/7x) user manual and that one doesn't know
    Rob> about a Data Watchpoint and Trace Unit (DWT).....

Look for any of the Cortex Technical Reference Manual manuals.
DDI0337E_cortex_m3_r1p1_trm.pdf describes the DWT as 11.5 DWT under "System
Debug", DDI0439C_cortex_m4_r0p1_trm.pdf has a whole section on "Data
Wstchpoint and Trace. The core_cm3.h and core_cm4.h in include/arch/cm3/
just checked into SVN contain the definitions, provided by ARM. The NXP
LPC178x/7x User manual "UM10470" clearly states on page 12 in the fourth
dot "The Data Watchpoint and Trace (DWT) unit is included."

Hope this helps
Uwe Bonnes                bon at elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
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