• CM4: Write buffer with enabled MPU

    Hello,

    I have a question regarding Memory protection unit on Cortex M4 (STM32F3 MCU). This is pretty simple single core MCU without caches. I implemented MPU based on instructions in Definitive guide to the ARM Cortex-M4. It is stated there that the bufferable…

  • Hard Fault on Cortex M0

    I am using a nRF51422 from Nordic Semiconductor with has an ARM Cortex M0 CPU.

    While trying to use their Bluetooth Mesh SDK I get a Hard Fault.

    I am trying to debug the example code to figure out what the problem is, and i am wondering under what circumstances…

  • What does "CMSDK_GPIO1->ALTFUNCSET = (1<<5);" do?

    Dear All,

    I came across initial function as the below,

    void UartStdOutInit(void)
    {
    CMSDK_UART2->BAUDDIV = 16;
    CMSDK_UART2->CTRL = 0x41; // High speed test mode, TX only
    CMSDK_GPIO1->ALTFUNCSET = (1<<5);
    return;

    }

    At the first time this function…

  • Detect RESET cause on Cortex M3 (STM32F107)?

    Hi.

     

    I have a problem HW-resetting an external HW-circuit on my PCB (my MCU is STM32F107):

    Because the POWER to my HW-circuits arrives later that to my MCU, I need to (re-) generate a delayed RESET-signal from my MCU towards the RESET-pin of the external…

  • ARM7TDMI memory spaces

    How many memory spaces are there in ARM microprocessors? Is there a separate memory space for program and constants? Are registers mapped into a memory space as in AVR microcontrollers? What is the maximum memory size for each memory space? What is the…

  • What is the difference between sparse and full example of cmsdk_ahb_busmatrix?

    Hi.

    As I know Cortex M3 design kit have lots of  stuff IP. one of those things is cmsdk_ahb_busmatrix.

    But I want to know does cmsdk_ahb_busmatrix supports AHB-full specification? or just supports AHB-LITE?

    I'm confuse that because there some example explained…

  • make talk two ARM Cortex M3 each other using WiFi or Bluetooth.

    9Hi,

    I want to develop a system with ARM Cortex M3  (LPC 1768 or LPC1343) can talk to each other ysing wifi module or Bluetooth Module. Plzz help in this contex as i am new toi ARM

  • 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…

  • Variation in the current consumption due to memory address and offset value?

    Hello to all,

     

    I am trying to figure out the variation in current consumption as well as in clock cycles due to different memory regions and different offsets. During various experiments, I have found the following results:

     

    LDR R4,[R1,#0x0]  (R1 = 0x00000000…

  • How to get to know the exact instruction address or find the instruction address for least current consumption?

    Hello to all,

    In order to measure the current variation due to instruction address location. I filled the memory with NOP instructions and tried to observe the variation in the current consumption due to change in the instruction address, although the…

  • Difference in the current consumption for different register place for few instructions

    Hello to all,

    While working on different assembly instructions, I have come across a very different problem of the register's place. For example: 

    SBC r11,r7,r11 : 3.0217mAmps

    but 

    SBC r11,r7,r7 : 2.7477mAmps

    Similarly, for ORN and MVN also.

    For all…

  • Example of instructions, doesn't use functional unit at all?

    Hello to all,

    I need a small help with the processor instructions. Can anybody provide me an example where during execution, the functional unit must not be used or it must be deactivated? 

    All data-processing and data-transfer instruction need the functional…

  • How to understand the behavior of hazard in Cortex-M4?

    Hello to all,

    I am working on Cortex-M4 and would like to know about the hazard situation. In order to see the effect of Data-Hazard, I have executed few application codes. For example,

    LDR R5,[R6,#offset]

    ADD R5,R8,R2

    LDR R5,[R6,#offset]

    ADD

  • How cortex-M4 handles data hazard situations in the pipeline?

    Hello to all,

    Since I am working on ARM Cortex-M4, I would like to know about the handling of the hazard situations (especially the RAW, WAR and WAW hazard situations) in the pipeline.

    Is the processor also use the method of "Forwarding" in order to handle…

  • Unidentified hardfault on Arm Cortex-M4

    I have a whole bunch of hardfault annotations - all of them show CFSR value as 0. I've tested the annotation mechanism with two intentional hardfaults (divide by zero and write through null pointer) and both recorded the correct CFSR value. Of course…

  • Cortex M4 (SIMD) - Fastest way to un-pack 1 (one) uint32 to 4 (four) uint8

    Hi to you all,
    In my current project I need to send over a serial bus an array of integers:

    • type = unsigned 32 bit integers
    • length = 4096

    The driver I'm using (actually USB CDC VCOM from NXP, which is embedded in LPCOpen) takes pointer to unit8 and…

  • ARM Cortex-M4 : Power v/s Frequency

    Hello to all,

    I am currently working on ARM cortex-M4. While I was running different codes of instructions, I have noticed an increment in the current consumption corresponding to the increment in the frequency. Or in other words, the higher frequency…

  • How does memory work in cortex M3?

    Hi 

    Now I'm trying to understand about memories in the Cortex design kit.

    I came across memory address map of cortex M3 when I googling as the below.

    In the image, left one is an AHB memory map, and right one is STM32F103's memory map.

    As you…

  • What is special with MVN instruction, when both source and destination register is same?

    Hello to all,

    Just wanted a small information about the MVN instruction, that when the source and destination register number is same, then why does it throw higher energy consumption? Since I have tried with MOV instruction also, but it's normal with…

  • PC doesn't update in simulation

    Dear All,

    Now I'm trying to digging the M3 operation in especially reset sequence with hello example of cortex design kit.

    Current situation is that reg14[31:0] is fixed in 0xFFFFFFFF and reg15[31:2] is 0xXXXXXXXX unkown value. the other regs are…

  • CORTEX M4 - Output an array declared with __DATA(RAM) attribute?

    Hi to you all,
    I'm using an LPC4370 (in a link2 probe) to output the data acquired @ 40 MSPS using the USB CDC VCOM driver included in the LPCOPEN Libraries.
    I can output an array of uint32_t elements and read it properly in Matlab at the host side…

  • Endian in Cortex-M4

    Hello to all,

    I am working on ARM Cortex-M4. Since it has 32-bit address bus, therefore I assumed that each 32-bit instruction will be allocated a physical address location in the Flash. But while reading the disassembly of the code, I got to know that…

  • Cortex-M4 Suspend/Resume Interrupts

    Hi together,

    im am working on a project managing high IRQ/ISR loads. (NXP S32K14x)

    On some critical sections i have to suspend global interrupt mechanism (cpsid i) and resume afterwards.

    Is it necessary to include a _dsb or _isb instruction after disabling…

  • How to use compiled Hex file from Keil on windows to the design_start?

    Hi,

    Thanks for your supporting in advance, As I know M0 or M3's design start kit have some example which is firmware such as Hello.

    If I compiled that Hello firmware in the window, then can I use directly into the design start kit? or should I need…

  • How does matrix4x2 implement in busmatrix?

    Hi,

    Currently I'm digging the bus matrix 4x2 bus matrix from 

    But I have some question.

    How does the bus matrix4x2 implement in bus matrix?

    I just draw what I've understand it as the below

    Am I understanding correctly?

    I want to understand internal…