Performance ratio between A35 and M4

Mohamed_Tarek

I am working on project and i used A35 to measure the performance of Application and this application will be ported on M4 , is there a fixed ratio or an equation so i can estimate the execution time of the application on CM4 ?

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Help me jump into ARM world !(I know nothing but AVR)

kamran

Hi, Sorry if this is a long thread but i'm really confused.

I program for AVR MCUs and also know about Arduino, I can program for different ATMEL MCUs with looking at datasheets, And i also programmed a few basic stuff on Cortex-M3 LPC1768, without…

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updating CPSR in USER UNPRIVILEGED mode

anoop

as we know supervisor mode is priviliged and user is not. at reset time in debugging mode, i read the cpsr it is 0x1d3 means in supervisor mode, so i can change CPSR so i changed it to 0x1d0 which is user mode, since user mode is unpriviliged so i must…

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STRD ATOMIC?

loquat

Hi, I make a software for Cortex-A9 and Cortex-M4 (both uni-processor system).

Question.

Is 64bit-aligned STRD(64bit memory access) atomic ?

(I know tha It is not atomic, but i don't know behavior.)

For example:

LDR R2,=buff

mov R0, #1

mov R1, #2

STRD R0…

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SWD for Time Profiling if no ETM Time Stamping is available

Andrea Bettati

Hi to you all, I'm using a LPC437 microcontroller (cortex M4) for a real-time application.
I would like to measure the performance of a function I wrote in C, i.e. know how much time does the execution takes.
Unfortunately my LPC4370 is not supporting…

xPSR change itself when branching

Tim Hsu

I am writing an embedded operating system targeting arm cortexm 4... I am working on context switching .. I can switch the kernel into user program and go back. but SVC call seems not work well.

syscall:
    svc SYSCALL_SVC_NUMBER
    bx lr

when calling…

Why is string defined with half '0's?

Robert

Hi,

I see the following C lines on a ARM M4 Cortex CPU. It is new for me to see those interleaved '0's among character letters.

Could you explain it to me?

Thanks,

const uint8_t g_pui8ControlInterfaceString[] =

{ 2 + (21 * 2), USB_DTYPE_STRING…

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LPC43XX (Cortex-M4): Timer triggered DMA transfer?

Andrea Bettati

Hi to you all,
thank you for your patience: I know I'm publishing a lot of LPC43XX related questions. but the support on NXP forums is just.. well, something different from the one I found here, so I keep taking advantage of your know-how: maybe one…

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Cortex M4 (LPC4370): how do I detect ADC threshold crossing while moving data in a DMA driven double buffer?

Andrea Bettati

Hi to you all,

I'm currently working on a project involving the LPC-Link2 as a eval. board for it's LPC4370 (for a complete explanation see this question).
What I'm trying to do is:

Continuously sample external analog signal (using on-board…

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'Sort and Count' program using Cortex-M3 Assembly (or less preferably in C language)

Vickey Khan

Construct the following null terminated string in code area (i. e. in ROM)

str DCB “p1er3fec6tst1r2an5ge7rs8”.0

Write an assembly program that will count and…

ARM Cortex-M3/M4 Toolchain and IDE

Guy Dillen

Hi,

I would like setting-up a ARM GCC Toolchain + IDE for developing for my Cortex-M3/M4 Processors (more types of cortex processors would be a plus). I downloaded GNU Tools for ARM Embedded Processors GCC ARM Embedded in Launchpad. What else do I need…

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C/C++ atomic operation on ARM9 and ARM Cortex-M4

John

I have a question about C/C++ atomic operation on ARM9 and ARM Cortex-M4. I am using ARMCC compiler with C / C++ languages. It interests me if it is possible that an interrupt will be handled in the middle of operations:

Read 8-bit character form structure…

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Cortex-M4 interrupt priority dynamically change while in ISR

Adnan Ashraf

Hello,

I am using STM32F407ZGT6 Cortex-M4 microcontroller. I am interested in changing the priority of a certain interrupt while servicing the same interrupt. Is that possible?

More elaborately, lets say I have an interrupt which has a priority of 4. The…

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Cortex-M4 interrupts behaviour when same interrupt vector has multiple interrupts

Adnan Ashraf

Hello,

I am using STM32F407ZGT6 Cortex-M4 microcontroller. This controller has same interrupt vector for 5 external interrupts i.e., NVIC (EXTI9_5) for EXTI5, EXTI6, EXTI7, EXTI8 and EXTI9 interrupts. They all have the same ISR EXTI9_5_IRQHandler interrupt…

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Bootloader in MK20DX256 32-bit ARM Cortex-M4?

Afnan Zafar

hi,

i am first time trying to use ARM processor, I have selected Freescale following processor.

MK20DX256

32 bit ARM

Cortex-M4

my confusion are:

1: I don't know how to load my program in my ARM processor?

2: is their any built-in bootloader in this processor…

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Usage of generic register in CPU reset

Kashif

Hi All,

Could anyone please tell me which generic register/location in memory can be used for storing a bit value which will not get reset after a CPU reset? I need the register to hold the value after a CPU reset so that I can know if a reset has happened…

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Cortex-M3 or -M4: Which is better?

Velagala J R N D V Reddy

Hi,

I need some clarification about which one is better either Cortex-M3 or -M4. Which one is present trending and which one having good future.

Thanks in advance.

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Flash programming in ASM for Cortex M4

Kashif

Hello All,

I am trying to write data into flash which i need to copy it to the SRAM later. I am doing this in assembly and this is part of the code i am trying to use.

I have provided the addresses of the FMD, FMA and FMC registers needed for flash programming…

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Loop unrolling on Cortex-M3 vs. Cortex-M0

Indu Girish

In the DSP lib files like arm_conv_f32, arm_fir_f32, the algorithm implementation in Cortex-M3/M4 and in Cortex-M0 is different. i.e., loop unrolling is used in M3/M4 and it is not used in M0.

Pls tell me the reason behind it. Is there any advantage of…

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