Questions tagged [arm]

32-bit microcontroller IP. The ARM company which designs the ARM cores doesn't make controllers itself, but licences the IP to other manufacturers. ARM is the leading 32-bit controller and is available from tens of suppliers.

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294 views

ARM Cortex cores with peripherals, basic requirements

I've been reading a lot of stuff about using ARM tool chain to build applications for different microcontrollers including ARM cores. Right now, I've been using the fairly easy route with Atmel Studio ...
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1answer
178 views

Develop Software for Microchip ARM Controller in MPLABX? [closed]

Is it possible to develop and debug software for a microchip ARM controller in MPLABX?
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1answer
85 views

ADuC702x MCU bandgap voltage reference question

I have recently started using the ADuC702x MCU family. I plan on using the analog to digital converter that comes with the MCU. The datasheet states that there is an internal 2.5V that it uses for ...
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1answer
560 views

FreeRTOS context switch ARM Cortex-M4

I am examining the context switching procedure on a ARM Cortex-M4 based processor running FreeRTOS. In port.c we have: ...
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1answer
192 views

SWD AHB-AP access gives ACK_FAULT

When attempting to debug a STM32L471RGT6 chip over SWD, I encounter an ACK_FAULT whenever sending an AP request to halt the core. I've implemented the following sequences which all work correctly, ...
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3answers
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Why is there a system controller and a microcontroller in the same FPGA?

I am starting to dig into the FPGA world. While exploring the FPGA SmartFusion2 architecture I found out that there is a microcontroller (ARM Cortex-M3) and at the same time a system controller. Why ...
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61 views

SoftConsole VS Keil for Smatfusion2 or any other development environment?

In order to program the ARM Cortex-M3 processor which is embedded in the Microsemi FPGA board SmartFusion2, I think there is two possibilities (correct me if wrong): Keil MDK (Microcontroller ...
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2answers
1k views

Keil : LPC1768 UART : Error: L6200E: Symbol a multiply defined (by main.o and uart.o)

I am learning ARM programming. I've configured uart of lpc2148 before. But there I included entire code in single file. Today I separated them in .c and .h file. But When tried to build, I got ...
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3answers
93 views

STM32F4 executable stack?

Is the stack executable on the STM32F4 MCU? I want to do this: ...
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2answers
711 views

Understanding ARM instruction for numerical literal

I have done an instruction trace while trying to find a bug on a Cortex M3. There is one part of the command I cannot understand. STRB R1, [R3], #+0x01 According ...
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1answer
154 views

Is there any single-board computer/system-on-a-chip with good documentation for developing bare metal? [closed]

I always wanted to develop my own crappy operating system, but the many weird legacy quirks of the x86/PC platform kept me from doing so (e.g. real vs protected mode, only low resolutions available in ...
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3answers
6k views

STM32F4 How are Preemption Priorities and Sub-Priorities used?

I have started working with ARM-based microcontrollers. I not understand subpriority and preeemptionpriority. For example: NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x00; ...
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2answers
979 views

AVR(or PIC) vs ARM for LoRaWAN nodes [closed]

Well, you can say that the title is a little bit misunderstanding. I do not want to compare these architectures, it's worthless. I am trying to understand why an engineer could ever pick for his ...
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959 views

How to connect Multiple JTAG devices?

Currently I am working on FPGA design which uses trace32 to interact with jtag devices. Since there are more than once JTAG device in the design we are using parellel (not daisy chain) approach from ...
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2answers
146 views

Designing an IoT product [closed]

This is more of a general question of the embedded electronics industry. At the moment I'm planning on building a device with a similar requirement to the Nest products. Essentially, I want to have a ...
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1answer
726 views

Cortex-M0 vs. Cortex-M0+ for an IoT sensor using LoRA [closed]

Although I am an experienced software engineer, I am still quite a novice in electrical engineering. So please bare with me in explaining my requirements: I have a small garden in my backyard and I ...
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785 views

Visual Studio Code for ARM

I use Atmel ARM chips and I'm used to use Atmel Studio 7 for developing. I want to try a more elegant editor for developing and I like the Visual Studio Code (VSCode). It's very nice editor. But I don'...
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1answer
227 views

Data during AHB Busy state

I have a question regarding the data during the BUSY state in a AHB bus. Consider the following example of an AHB master writing data onto an AHB slave: ...
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2answers
171 views

ARM chips that lack boot ROMs [closed]

This isn't anywhere near as true as it used to be, but I consider one difference between x86 platforms and ARM platforms to be whether or not booting involves the use of a mask ROM at reset to ...
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2answers
388 views

Multiplex usage of I/O pins: PWM pulse output + UART

I have the problem, that I have a device with limited output pins and want to know if it is possible to implement a multiple pin usage with additional HW/SW (time multiplexed mode). In my case my ...
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406 views

Why doesn't my STM32F4 PLL seem to work?

I've spent a few days unsuccessfully trying to get my Nucleo F401RE to use the PLL for its system clock. I've configured it to use the 8MHz HSE and output 84MHz as the system clock. The code stops ...
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0answers
1k views

IP over LwIP PPPoS with Telit GSM GL865 and STM32F7

I am using Telit GL865 GSM Modem with STM32F7 nucleo development board. I make them communicate via USART1. Firstly, I configure the modem with AT commands as below; after that, modem starts to send ...
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1answer
246 views

Why am I not able to compile this assembly code?

When assembling the code, I get the error : fpu.s(13): error: A1240E: Immediate value cannot be used with this operation ...
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0answers
513 views

Wrong FFT result when using rfft function on STM32F4

I'm trying to use rfft function in STM32F407G and I am getting wrong results when I compare it with an online fft calculator . I give a sample input as {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,...
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1answer
118 views

stm32f429 flash load address error

I've recently run into this error where openocd wont flash the binary to my discovery board. I'm using the same linker script that i've been using all along. arm-none-eabi-objdump gives the ...
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1answer
160 views

ARM SoC UART interaction with peripheral UART

I am sorry that I couldn't find this answer in this site or web. I have an ARM SoC(Host) which needs to communicate with the peripheral having ARM Micro controller using UART. Linux runs on top of ARM ...
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2answers
399 views

LPC1768 Baud rate

I've been trying to configure UART module of LPC1768. Board comes with a crystal oscillator of 12Mhz. It does nothing more than receiving a character and transmitting it at the same time. I am using ...
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1answer
61 views

Delay function for a STM32L152

I want to implement a very simple delay function with more or less this look: void delay(float seconds){ int i; for(i=0; i<seconds*5000000; i++); } It is ...
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1answer
736 views

What's the need of translating the virtual address to physical address?

These are the points I read in the Memory Management Unit of ARM architecture: Virtual addresses (or logical addresses) are addresses provided by the OS to processes. One virtual address space per ...
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1answer
321 views

STM32F3 CAN Hardware not Entering Init Mode

I'm trying to write a bare metal driver for the STM32F302 on a Nucleo-64 board. I'm having trouble getting past the very first steps and getting the hardware to set the Initialization Acknowledgment. ...
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1answer
152 views

How does the ARM Compiler (Version 5) handle double-precision floats in devices whose floating-point unit hardware only supports single precision?

After reading ARM Compiler version 5's manual, it says that for devices without a floating point unit, floats are dealt with through software implementations, which is likely going to be slower than ...
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1answer
1k views

Programming STM32F3 with Atollic TrueStudio: arm-atollic-eabi-objcopy says No such file

I am using the newly-made-free Atollic TrueSTUDIO for STM 32 and built a CMSIS-based STM32F3 project from scratch. When I try to build the project, I get the following Build Console error: ...
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1answer
217 views

Can't run code in Keil for STM32L433RCT6P on NUCLEO-L433RC-P

Recently at Embedded World 2018 in Nuremberg I got, for free, NUCLEO-L433RC-P with STM32L433RCT6P chip onboard. I want to broaden my knowledge in STM32 chips. Before, I did simple stuf on STM32F4. ...
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2answers
93 views

RS 232 - 4th pin purpose

I have been using the schematic of MCB1700 Evaluation board in my customized ARM Powered board. I planned to use RS 232 communication on my board. When I go through the schematic, I am stuck with the ...
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0answers
1k views

STM32L4 bootloader unable to enter application

I've been following bootloader guide here and trying to write a bootloader that simply turns an LED on when entering a pushbutton-induced performFirmwareUpdate(). I'm using the ARM GNU toolchain in ...
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2answers
190 views

Configuring Registers in ARM Cortex M3

I've been learning to program LPC2148(ARM7) microcontroller, and today I got hold of an LPC1768(Cortex M3) board. By referring it's manual, I tried to make a LED blink program and did it as follows, ...
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3answers
409 views

Rowley Crossworks STM32 Start from Reset

I am using an STM32F4 with the Rowley CrossStudio for ARM. It is not clear to me how to have the MCU start from int main() on reset (i.e. power up the device). I thought building it in release mode ...
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3answers
403 views

Does using a software delay() function have greater power consumption than using a System Timer interrupt? [closed]

I had a discussion with someone about using a software delay(), and how it just executes NOP commands for a specified number of clock cycles according to your delay, and thus is constantly running and ...
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0answers
163 views

SOC vs ARM Core

I am trying to understand the difference between SoC ( System on Chip ) and ARM Core. In the following post, I have read "The typical ARM processor in use today is integrated with peripherals on a ...
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4answers
2k views

Software Debouncing to detect if switch has been pressed for T seconds

I need to detect if a switch has been pressed for longer than a set time, without using any Timer registers in my embedded code. I am using software debouncing in the following manner to detect a ...
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0answers
256 views

register bit access using structure union combinations

I have a structure something like this in device header file: ...
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1answer
547 views

Placing a key variable in internal flash Memory

I am trying to place a variable named secret_key at location 0x08002000 in STM32Nucleo-board which has STM32L476RG on board with 1MB flash. Question 1: Why am i ...
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1answer
170 views

Multicore ARM how to assign a critical task to one dedicated core [closed]

Suppose I have a multicore ARM processor (to make it simple assume 2 cores with an unshared cache between the 2 cores). Suppose my system contains a critical task and several non-critical tasks. ...
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1answer
67 views

ARM LCD driver internal workings

I want to use LCD driver pins to light up LEDs instead of using LCD screen. This is done on a broken device so altering other pins is not possible for this case. Is this safe to CPU to connect just ...
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2answers
101 views

Design an instruction using Thumb-2

I'm studying the Cortex-M3 of ARM. The problem statement reads: We're going to use a Harvard architecture with the following addressing capabilities: 32M words of code and 16-bit data words. The ...
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1answer
70 views

Does ST have a separate Cortex M4F series or are its M4 parts essentially M4Fs?

ST's website does not use the term M4F. Also there is no filter for Hardware Floating Point Unit in parametric search so I guess ST includes floating point unit in all M4 parts.
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2answers
72 views

Why is the cache size identification register on ARM CPUs accessible from privileged modes only?

Is there any logical decision making behind this, to my understanding it exposes only the same information as CPUID instruction from x86 so why is it only made accessible to EL1? Is this in some way ...
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1answer
82 views

How is translation granule set in ARMv8-A processors?

ARMv8-A supports three different translation granules, viz. 4K, 16K, 64K. However the programmer's guide doesn't speak how this is set. What field of which register controls the granule setting? Can ...
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1answer
133 views

How does TTBCR affect low addresses in ARMv8-A?

While reading about translation tables in ARMv8-A, I came across the following: Depending on the size of the possible VA range, there can be even fewer levels. With a 4KB granule, for example, if ...
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1answer
74 views

Counting slow to fast in a microcontroller.(Ramp)

I want to make an increment(++) to a variable initially slowly then speed up linearly. For example, using a timer interrupt(every 1 sec) in increase the variable x by 1.so at first variable get ...

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