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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81 views

Going from PIC to ARM

I've been wanting to expand my embedded skillset with ARM MCUs after spending a few months working with pic24 devices but I've hit a roadblock. I wanted to start programming ARM more "on the metal" ...
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2answers
512 views

Cortex M7 goes to HardFault immediately after reset

I am using the ATSAME70Q21 processor with a Cortex-M7 CPU. My development environment is Atmel Studio 7. I am using the SAME70 XPlained demo board. I am creating some code in assembly language. As ...
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105 views

LPC1768 vs Timer0, etc

I realise that the LPC1768's Systick is a standard accross ARM boards, while Timer0 and co, are NXP additions. Is there any particular reason to use one over the other? Say you want to generate a ...
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SWDAP vs CMSIS-DAP vs DAPLink

EDIT : I got the basic questions (for example, what is CMSIS-DAP?) answered by user @Nipo. Based on that, I restructured my post in a more logical way. Hopefully ...
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241 views

Protect Code inside Microcontroller [closed]

As a preface, what I am asking is highly related to this question. That said, the question linked was asked in 2011 (7 years ago), and I imagine the microcontroller world has changed (at least to ...
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368 views

What is the difference between system clock and peripheral clock in case of arm Cortex M4 architecture? [closed]

System clock/core clock is the clock that drives the CPU. I understand that different internal peripherals use the oscillators. How do both differ from each other?
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52 views

Using narrower DDR RAM than controller

I have some ARM processor that have 72-bit width (8 for ECC) RAM controller. Can I buy eg. two 32bit chips and combine them? If yes then how? Can I buy just one 32bit and pull down rest of data pins ...
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1answer
1k views

Chip Erase vs. Sector Erase

In Keil IDE Software there are two ways to erase chip before program it. What does do "Erase Sectors" mode? When to use "Erase sectors" mode and when to use "Erase Full Chip" Mode?
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1answer
116 views

LPC2148 baud rate equation

I'm little confused about the baud rate calculating equation of LPC2148 In data sheet equation is But in every tutorial I could find equation is Second equation sets the baud rate as required. ...
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1answer
87 views

How to interface SN74 buffer with microcontroller into another data bus

I am hoping to interface a 3.3V ARM M4 microcontroller into an already established 5V data bus, and have it respond to interrupts to either read data from the bus or write data to the bus. The data ...
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328 views

Booting from SD card in SPI mode

I want to boot an ARM Linux board (Allwinner H3 for example) from a generic (micro) SD card through an SPI interface. Can an SD card accept SPI communication right away or is there any "SPI mode ...
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Are some CPUs implemented in standard cells and are others customized?

Explaining the question more, I see some die pictures which are implementing a Cortex-M0, with Bluetooth LE and so on, depending on the chip functionality, and are appearing like this (nRF51822): ...
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135 views

Cross GNU ARM Toolchain

As a beginner, I am confused with setting the adequate toolchain (the whole concept in new for me). My goal is to program the ARM Cortex-A9 on the board Zynq 7000 using the Xilinx SDK. In order to ...
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3answers
3k views

Atollic STM32H7 + ST-LINK Error writing data to flash with math library

I am currently working on a STM32H743VIT6 chip (on a self-designed board), with the Atollic TrueStudio toolchain (ver. 9.0.0), using a ST-LINK debugger on a STM32F4-Discovery board (ST-LINK firmware ...
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Nested Vectored Interrupt Controller (NVIC) - Why is it “nested” and “vectored”?

In ARM microcontrollers there is an peripheral called NVIC (Nested Vectored Interrupt Controller). What does the "nested" and "vectored" part refer to, or why is it "nested" and "vectored"?
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343 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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209 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
93 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
699 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
218 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
1k views

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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72 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
2k 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
115 views

STM32F4 executable stack?

Is the stack executable on the STM32F4 MCU? I want to do this: ...
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2answers
1k 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
180 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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9k 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
1k 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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2answers
2k 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
156 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
787 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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798 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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293 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
257 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
469 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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487 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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1answer
333 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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579 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
136 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
173 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
483 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
72 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
1k 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
385 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
180 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
2k 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
247 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
96 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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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
207 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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