Cortex-M is a series of ARM processor cores intended for microcontroller applications. ARM licenses the design to third-party chip manufacturers and does not manufacture devices themselves. They are promoted as being suitable for low-power / cost sensitive applications that still need high ...

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3
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3answers
379 views

STM32 non floating point unit chips

I would like to know how STM32F2 chips and below that doesn't handle floating point unit, perform float operation. I read here, it mentions that the floating point is handled by library functions, ...
-3
votes
1answer
101 views

How do I go about putting uCLinux on a cortex M7? [closed]

I would like to be able to run uCLinux on a cortex M7 board, but don't know where to start. I've searched the net and found a video demo of somebody who got it to work but no tutorials or anything.
-2
votes
2answers
129 views

STM32L4 USART problem

I tried to develop an USART example on stm32L476 discovery kit, but I've got some problems with the HAL driver-s, I think I'm using wrong USART interface Clock enable, and USART GPIO Clock enable ...
0
votes
2answers
64 views

Fill ROM with jump instructions

As I have heard it is a common practice to fill the unused flash memory of a microcontroller with an jump instruction to the reset function. This aids in resetting the MCU in case of the PC is corrupt,...
2
votes
2answers
83 views

Systick interruption doesn't trigger when handling another interrupt

I am experimenting with the STM32f4 discovery and i tried to use a delay (based on SYSTICK) in an ...
2
votes
3answers
359 views

What happens on STM32 when multiple (UART) Interrupts are triggered at the same time? is there an interrupt stack?

I'm implementing a uart daisy-chain communication scheme with a Cortex M4. When a node receives a byte over one UART, an interrupt is generated (RXNE) and the byte ...
0
votes
2answers
144 views

Design Consideration: Cortex M0 vs Cortex M4 for IoT Applications [closed]

I'm designing an IoT Device with many sensors which are going to be integrated using serial interfaces like UART, SPI, I2C and so on. For communication capabilities, I plan to use Wi-Fi (IEEE 802.11). ...
0
votes
1answer
96 views

FRDM-KL25z assembly delay loop causes reset

I'm currently working on a project using the FRDM-KL25Z development board and programming using Keil MDK-lite (5.14a). What we're supposed to do is create a simple traffic light using three ...
1
vote
1answer
28 views

Mutex in RTOSes in this specific situation

Consider the following codes: ...
3
votes
1answer
320 views

ARM startup file attributes vs GCC command line arguments

The startup files for STM32 Cortex-M MCU's, for most GCC toolchains, often bundle the Atollic TrueStudio startup assembly files with HAL libraries, like for example in my case, STM32CubeF4. I'm ...
2
votes
1answer
89 views

stm32f3 DMA not sending data array properly

I have a peculiar problem with STM32F303 DMA. I am using libopencm3, but I hope you'll clearly see what is happening - it's all just functions to set the control registers. I am sending data from a ...
1
vote
0answers
108 views

STM32F411 - I2C failure during heavy polling load

I have a STM32F411 communicating to 2 peripherals (an IMU - MPU6050 from Invensense, and a LED Driver - CAT3626 from ON Semi) over its 2 I2C buses (one peripheral per bus). I'm running into a strange ...
0
votes
1answer
59 views

Cortex M0 or M3 serial interface to ARM7

I have worked on ARM7 controller (LPC2138) for my application. But now to add NFC module I am using LPC1227 controller along with NFC chip. ( Both dies in single package ) Now, if I want to ...
0
votes
1answer
817 views

STM32F4 TIM2 timer, getting to 1 second

I'm learning a bit about general purpose timers on my STM32F4Discovery board, and would like to know how I can configure the timer to invoke a timer interrupt each second, or at least have the auto-...
1
vote
1answer
118 views

How to use CMSIS to set up bidirectional Port on STM32F4

I'd like to use the GPIO_TypeDef an GPIO_Init to create a bidirectional Port on the STM32F407, some input pins, some output pins. Do I just run GPIO_Init twice, once for the input pins and once for ...
0
votes
0answers
127 views

Video via STM32F746NG (ARM Cortex M7) VS SM320DM6446 (ARM9)?

I am interestedin getting a Video feed from a CMOS sensor module like the OV2640 or OV7670. I found that the STM32F746NG has a camera interface which is useful, but I also found out that the ...
1
vote
2answers
417 views

Difference between ARM A and M series processors?

When I'm asking this, I think on microcontrollers, whats the difference between A and M series of ARM processors. Many microcontrollers such as Beagle Bone now have A type of Cortex?
0
votes
1answer
138 views

Are unaligned LDRH/STRH supported on Cortex M3/M0?

Can all Cortex M0/M3 cores do this? LDRH r0, [0x8001] This would suggest yes but I don't see anything specific about Cortex-M cores.
0
votes
2answers
427 views

UART interrupt problem on LPC1788

I wrote a code ...
7
votes
4answers
2k views

My first STM32 code - please criticize me

I have just wrote my first code on STM32 - blinking LED. It combines a fragments from different sources; please criticize me so I can learn how to write proper code and don't learn stupid habits. <...
2
votes
1answer
67 views

Managing addresses of interrupt service routines and functions of the program in cortex M0

I am working with nordic nRF51422 uC with cortex M0 core and I have to store data in Non-Volatile Memory but to do that properly I need information where exactly code of the program is stored in flash....
0
votes
1answer
236 views

Any Cortex-M3(LPC1768) compilers for Linux? [closed]

Are there any uVision alternatives for Ubuntu/Linux?, i know about LPCxpresso, but i just don't like it and its only for LPC MCUs. i tried Googling and it didn't help, I only saw results about ...
1
vote
0answers
233 views

CRC32 on SAM D20 (Cortex M0+)

I've been having a hard time debugging the DSU module on a SAM D20 (datasheet). I mean to utilize it to calculate CRC32 for a program I'm uploading through a custom bootloader (bootloader not mine). ...
6
votes
1answer
1k views

What is relation between ARM libraries

What is relation between CMSIS libs released by ARM.com, libraries provided by manufacture and GCC ARM libraries ? What is the exact purpose of each? Which of them Should I use?
0
votes
3answers
2k views

Which ARM MCU family is better for beginners? [closed]

Which ARM MCU family is better for beginners? I mean which family: Is straightforward and easier to learn Has more/better learning and development resources available Has bigger and better ...
4
votes
1answer
3k views

STM32F4 boot concepts and vector table relocation

There are some things I don't understand on the boot process of the STM32F4 microcontroller. My understanding is as follows: The ARM Cortex-M4 boots expects the stack pointer initialization value ...
8
votes
3answers
1k views

RTOS for Cortex M4 with 802.15.4/6LoWPAN stack

I'm evaluating operating systems to use in an Internet of Things Project and I don't know what's the best way to proceed. I'm using a TM4C123GH6PM MCU with 32k RAM and a CC2520 802.15.4 transceiver, ...
1
vote
0answers
591 views

STM32 ADC: Multiple channels with different sampling rates

I am trying to figure out how the STM32 multiple channels ADC conversion works (regular group). Lets say I want to convert on two channels, channel 1 and channel 2, on ADC1 and the sampling rates are ...
1
vote
2answers
758 views

Assembler coding for ARM (Cortex-M0 and M3): is it possible/practical?

Unfortunately there are no questions on Stack regarding ARM and assembler at all. My concern -- is time critical devices. Let's take for an example one of my AVR-based device (program compiled with ...
1
vote
3answers
919 views

Do I need OS for ARM Cortex-M0(3)?

I'm a developer of control devices for switch mode power supplies which need to generate a PWM signal(s) with a frequencies about 100 kHz, measure analog signals, communicate vie USART, make ...
0
votes
1answer
225 views

SD Card Access Library

I am accessing my SD card using SPI. But I've found this to be slow and I am also sad that when there is a faster protocol already supported by my SD card I am using a slower version. Is there a C ...
1
vote
2answers
55 views

Why doesn't the MCU's pin go high on time?

I have a STM32F103 and I downloaded this program to it(a simple blink program): ...
1
vote
2answers
272 views

Measuring power consumption of a design ranging uW to tenths of mW

I want to measure the power consumed by my design ranging from uW to tenths of mW. Power values I wish could be recorded digitally so that I can use them for analysis later. May be another form is ...
1
vote
1answer
229 views

Code Security of ARM Cortex M4 MCU

What are the main methods the code inside a certain ARM Cortex M4 MCU (TI LM4F120H5QR etc) can be extracted after deployment? Is it possible to completely stop a third party from stealing the code ...
2
votes
1answer
758 views

External MMU for cortex-M

The Cortex-M processors are getting faster and more powerful. The Cortex-M7 has just been announced. Yet these cannot run Linux (other than uCLinux) because the chips lack an MMU - Memory Management ...
0
votes
1answer
510 views

ARM Cores Benchmark

I am taking some deep interest lately in the ARM architecture and there are many flavors of ARM out there....ARM7, ARM9, ARM11, ARM Cortex-A, ARM Cortex-M and etc. Are there any benchmarks of all the ...
1
vote
2answers
190 views

ARM cancel execution of pre-empted interrupts

I can't seem to find an answer to this in google or the Definitive guide... Is it possible to from one interrupt, cancel the return to any pre-empted interrupts? For example, I have an ISR which is ...
2
votes
1answer
552 views

What's the concept of these three options for configuring the memory of STM32?

I have read the STM32F10x Reference manual but a section about "Reading the Flash memory" is not clear to me, yet. I mean this part(page 59): I have several question: What's the Latency? in fact ...
2
votes
1answer
115 views

The same flag for an interrupt

I think I'm mixed up a bit in NVIC of stm32 MCUs. I took a look in the SPI.h of the STM32F10x standard peripheral library. I don't know that why while there is ...
2
votes
4answers
806 views

minimal ARM (cortex m0) board

First: I'm not a professional. I just want to know what is possible and if i'm on the right track. Second: I want a little microcontroller which just measures (for example) the temperature and send ...
3
votes
2answers
274 views

Moving code from an ARM M0+ to an ARM M4, what changes?

Say I have a very simple program that functions perfectly fine on a ARM Cortex M0+ processor. How much will I need to change in order for it to work on an ARM Cortex M4 processor, assuming they are ...
-2
votes
1answer
290 views

Recomendation for simple Cortex-M Flash Programmer [closed]

Looking for a recommendation for a simple, inexpensive, flash programmer for the Cortex-M - specifically the nRF51822. My project is ready to move into the short run prototype stage and I need to ...
1
vote
2answers
1k views

External Code Execution on ARM Cortex M

Is it possible to run code on the ARM Cortex M architecture from locations other than the onboard flash memory (such as another flash chip, SD card)? If so, how? If not, what microcontroller ...
8
votes
4answers
2k views

What are the differences between rand() function and RNG (Random number generator) peripheral?

I'm wonder for RNG (Random number generator) peripheral in STM32F4XXXX MCUs. look in this Reference Manual (page 748). On the other hand, we have the rand() function in stdlib library that do the same ...
0
votes
1answer
178 views

Writting Joystick drivers for ARM Cortex [closed]

I need to write a driver for Xbox360 joystick controller, using its module and everything. The idea isn't just take the code, I'm really interesting in the theory behind it. Does anyone have any ...
4
votes
3answers
721 views

Is there any difference between the assembly instructions of ARM MCUs from two different corporations?

I'm curious to know, are there any differences between the assembly instructions of ARM MCUs from two different corporation? For example between an Cortex-M3/4 of NXP and TI or ST or other ...
4
votes
3answers
3k views

STM32F4 - Floating point unit ( FPU )

I would like to know, what is the purpose of the special FPU unit, that is advertised with STM32F4 microcontrollers ? To quote this website : " The Cortex-M4 core features a Floating ...
3
votes
2answers
596 views

Can Tiva C run code from SRAM?

All I know is that although Cortex-M3/4 micros are Harvard architecture, they can run code from RAM, at least some implementations can (like STM32F4). Can Tiva C series microcontrollers execute from ...
0
votes
2answers
494 views

Force Cortex-M3/4 reset from assembly

I would like to force my STM32F4 to reset on fault, I tried to copy NVIC_SystemReset in assembly as : ...
8
votes
4answers
6k views

Endian problem on STM32

I'm using arm gcc (CooCox) to program an STM32F4discovery, and I've been wrestling w/ an endian problem I'm sampling with a 24 bit ADC via SPI. Since three bytes are coming in, MSB first I had the ...