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  • Does anyone use assembler only with an ARM MCU?

    I have only used assembler when working with MCU's. I can follow a C program but have not used it in any commercial product. Can anyone suggest a development platform to start off learning the ARM and C? I would probably work on a Cortex M4F as a start…

  • How to get absolute value of a 32-bit signed integer as fast as possible?

    Hi.

    I wonder how to calculate absolute value of a 32-bit signed integer in C as fast as possible. I saw that there is a FPU instruction VABS.F32, which do that in one cycle (above the floats). I thought, if it is possible to use it also with integers …

  • Bit-banding in SRAM region (Cortex-M4)

    Hi.

    I would like to use bit-banding feature in SRAM, but don't know exactly how to implement it with C. I already use bit-banding in peripheral region with this kind of macro:

    #define BITBAND_PERI_REF        0x40000000…

  • cmsis NVIC question.

    Hello, Everybody. I have several questions.

    1. Please See the NVIC_Type structure. I don't understand about why ISER,ICER,ISPR and ICPR use size of array 1( I think It can use just __IO uint32_t ISER; ), and what does RESERVEDs do???

    2. I would like…

  • Cortex M4 exception return sequence

    Hi,

    I think I am just getting confused with this even if (or because of) I read the book and manuals again and again.

    At exception entry, the processor saves R0-R3, R12, LR, PC and PSR on the stack. Saving PC means that the address of the instruction to…

  • Get current active interrupt priority

    Hi everybody,

    We are working on a simple priority RTC (run to completion) framework for the Cortex M3/M4. Thanks to the NVIC/BASEPRI, we got most of this functionality for free but we want to extend it to user tasks.

    In our implementation we need to determine…

  • FFT C-File

    Hello everybody,

    im using the Math.h file to do a rfft with 1024 points und q15 datatype.

    So far everything works fine, and I get good results. It needs a computation time of ~720us on my CortexM4 @100Mhz.

    This is very Impressive, but to long for my application…

  • ECG, Wavelets and Cortex-M4

    Hello
    First of all a successful 2017 for all of us.

    I'm looking for examples of C algorithms for applying the concept of wavelets to identify ECG patterns in data collected with a Cortex-M4, preprocessed and later sent to a Cortex-A for graphical re-ordering…

  • Cortex M4 Conditional Branch - Pipeline

    Hello all!

    So I'm working on a development with a Cortex M4 and there is something i don't understand, I was hoping someone could help clarify this:

    This is the code I' using

    (Assume R3 content is 1, R6 R8 the address needed to set PIN1, and…

  • Current Variation due to Functional Unit activation or deactivation

    Hello to all,

    I would like to measure the current variation due to Functional Unit activation and deactivation. Can anyone help me out with the assembly program or the code through which I can measure this? I am using LPCXpresso 54114 board(ARM Cortex…

  • Cannot init heap using scatter file and C++ startup (Cortex-M4)

    Hello,

    I need help with heap initialization using scatter file and C++ startup.

    MCU is STM32F407VGT6 (Cortex-M4).

    Compiler is ARM Compiler 6.7, C++14.

    The problem is that all variables which I create dinamically on the heap have wrong addresses. My HEAP…

  • [C++11][Cortex-M] - distortos - object-oriented C++ RTOS for microcontrollers

    Hello!

    I finally decided to share some info about a project I've been doing for the past 8 months. Currently it can be considered "alpha" or maybe "early beta" stage, but - despite literal meaning of these terms - the things that are already done (and…