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Questions tagged [cortex-m3]

is an ARM 32bit RISC processor core for microcontrollers

28
votes
7answers
27k views

Linux on ARM Cortex-M3 series

I'm new to ARM and a bit confused with all the diferent series. I need to build a low power gateway (ethernet, wifi...), so I guess a cortex-M or cortex-R will be the good starting point. But it didn'...
21
votes
5answers
4k views

Cortex-m3 toolchain

I am looking for a free (as in freedom) tool chain for Linux (Ubuntu) that allows me to develop for an ARM cortex-m3 (lpc1343) microcontroller. Where do I find such a toolchain? Are there any ...
16
votes
6answers
11k views

Smallest embedded linux distro?

I like to ask to the experts out there.. What is the best embedded linux distro for: Flash memory ~ 700Kb Ram ~ 256Kb Processor: High end arm cortex M3 (something from STM32 family for eg) Required ...
15
votes
5answers
24k views

Best pattern for WFI (wait-for-interrupt) on Cortex (ARM) microcontrolers

I'm looking into developing battery-powered software using the EFM Gekko controllers (http://energymicro.com/) and would like the controller to be asleep whenever there's nothing useful for it to be ...
12
votes
5answers
3k views

Cycle counting with modern CPUs (e.g. ARM)

In many applications, a CPU whose instruction execution has a known timing relation with expected input stimuli can handle tasks that would require a much faster CPU if the relationship were unknown. ...
12
votes
3answers
15k views

Any ARM based microcontroller with integrated WiFi? [closed]

I am looking for a ARM based low cost SoC with an integrated WiFi, tried different search engines and still not been able to locate one. I would like to know if anyone knows of such device that has ...
10
votes
3answers
10k views

Critical sections on Cortex-M3

I'm wondering a bit about implementing critical code sections on a Cortex-M3 where exceptions are not allowed due to timing constraints or concurrency issues. In my case, I'm running an LPC1758 and I ...
9
votes
1answer
6k views

Storing a secure key in an embedded device's memory

I am working on an embedded device which send/receive data and stored them in ciphertext mode (encrypted mode). Now what's best approach for storing keys (I used ARM CORTEX M series MCU)? 1-Storing ...
9
votes
4answers
1k views

Building a circuit with LPC1343

Have people here used the LPC1343 Cortex-M3 chip? I've built a few small circuits with PIC microcontrollers before but now I'm using an LPC1243 Cortex-3/ARM. I've been using an LPCXpresso prototype ...
8
votes
3answers
2k views

BSD style Open Source alternatives to CMSIS?

Since the licenses on CMSIS is unclear when it comes to open source, it is probably a violation to include the CMSIS in a open source project regardless if it using a GPL or BSD style license. Is ...
7
votes
3answers
7k views

Error when compiling start-up file on STM32

I am attempting to provide custom interrupt handlers for my Cortex M3 (reference manual here). ST kindly provides a standard library, which has various startup files all called "startup_stm32f2xx.s". ...
7
votes
2answers
1k views

Problems programming LPC1343 microcontroller in Ubuntu

When I copy a binary that works on a lpc1343 to the mounted usb-device representing the lpc1343 flash, the binary file is changed and does not work. Doing the same with the flash mounted via usb on ...
6
votes
1answer
421 views

What are the things to watch out for when switching from AVRs to Cortex M3?

I've just recently gotten my Cortex M3 (LPC1343) up and running, following Microbuilder's instructions to get a GNU C compiler working for it. I've run some example code and in general, the code seems ...
6
votes
2answers
878 views

LPC1788 reading via SPI from ENC28J60

I have a problem with SPI communication with ENC28J60 chip. Basically I can't use SSP in SPI mode as it is, because ENC28J60 expects CS to be low for multiple bytes while SSP shifts it high after each ...
6
votes
2answers
637 views

Mysterious hard-fault when I step over

This question was rewritten to remove several updates and improve clarity. I have a Cortex M3 based (and rather obscure) MCU. I have a rather big project, written in C++, in Keil MDK5 with armcc ...
6
votes
2answers
2k views

How do I get started with uCLinux?

Right now I have ported an application from LPC2478 to Cortex M3 (LPC1788) and things are working fine at 120MHz. I am thinking of porting uCLinux to my LPC1788 custom board. The board consists ...
5
votes
1answer
3k 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 I ...
4
votes
3answers
1k 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
4k views

Program only runs when debugging in GDB - using Open OCD and Olimex arm-usb-ocd-h jtag to program at91sam3su

I'm trying to make my Atmel at91sam3u cortex-m3 arm chip make an LED blink. I have a Olimex ARM-USB-OCD-H jtag programmer, and I'm using Open OCD running on OS X to program my chip. I'm using the ...
4
votes
2answers
13k views

setting the frequency of a PWM on a STM32

I'm trying to write a function that takes a desired frequency of PWM and sets the timer based on this value: ...
4
votes
3answers
3k views

Sleep on Arm Cortex

I'm trying to put a cortex m4 processor (m3 with dsp extensions) to sleep for a little less than a second. I want to be able to tell it to sleep, then a second later, or when a button is pressed, pick ...
4
votes
2answers
412 views

Interfacing microcontroller with 1.8V logic

I am in the process of selecting a microcontroller to interface (~30 signal lines) to an FPGA that operates at 1.8V voltage levels. I have found NXP's Cortex M0's to operate down to 1.8V which is ...
4
votes
2answers
596 views

Can the ARM processor be switched to unprivileged mode inside handler mode?

In the ARM documentation it is stated that: The processor supports two operation modes, Thread mode and Handler mode. Thread mode is entered on reset and normally on return from an exception. ...
3
votes
6answers
2k views

What instruction on the STM32 consumes the least amount of power?

The ADC module of the STM32 is used in my application which is very sensitive to power consumption. In this application, the ADC is required to work only at 20 samples per second. Using the DMA uses ...
3
votes
3answers
9k views

Laying out a 10-pin JTAG/SWD connector on a final design

I'm designing a board with an ARM microcontroller on it (LPC1347FBD48) and I want to include a 10 pin jtag/swd connector, as is standard, for in-circuit debugging of my final design. Here is the ...
3
votes
1answer
4k views

STM32 USB - Delayed transmit when payload length = 256 (or 512, or 768…) bytes?

I am implementing USB communications on a STM32F105, using ST's USB Library v2.1.0. It communicates as a CDC class Virtual COM Port ("VCP"). I'm using the embedded Full Speed PHY. I've started with ...
3
votes
2answers
796 views

Power line communication, how to check if frequency is present

I'm trying to communicate on a power line without external filters (only a filter for the 50/60Hz), because I want to use only digital filters. My processor is a Cortex-M3 device running at 24MHz. ...
3
votes
3answers
862 views

Does lack of MMU make any difference for applications?

Generic Linux can't be run on Cortex M3 because Cortex M3 has no MMU. Okay, there're special versions of Linux that can run there. The problem is I don't quite get how this affects application ...
3
votes
3answers
2k views

How fast can ARM Cortex M0s/M3s bit bang?

I have not yet used ARM Cortex uCs, only AVRs Firstly, how fast can they: Stream 1024+ bits (serially, from bytes in RAM) out of a pin, with no pauses/jitter Stream 1024+ bytes (parallel, from RAM) ...
3
votes
2answers
204 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 ...
3
votes
4answers
4k views

GUI library for HMI Cortex M

Hi I am basically using cortex m3 series of processors for our application. I am looking for some GUI library that can be used for HMI. Is there any GUI libraries available? I recently heard about Qt. ...
3
votes
2answers
491 views

Programming SRAM over SWD

I'm attempting to program a Cortex M3 based microcontroller over SWD, more or less from first principles. I've written an SWD interface library and have it running on a second micro. I've largely ...
3
votes
1answer
1k views

Examples of schemes for Microcontrollers STM32

On the Internet a lot of tutorials on AVR microcontrollers, but very few examples for novice developers to STM32. Who can give a link to educational materials for STM32? Interested in the scheme ...
3
votes
3answers
218 views

Finding maximum source impedance for A/D converter (SAM3X8E ARM Cortex-M3)

I would like to find out what is maximum recommended source impedance for A/D converter on Atmel SAM3X8E ARM Cortex-M3 microcontroller. I tried to follow the example of this excellent answer, which ...
3
votes
1answer
1k views

How to use level-triggered interrupts with STM32F1xx?

I'm getting conflicting info on whether I can use level-triggered (as opposed to edge-triggered) interrupts with the STM32F1xx microcontroller. In ST's CMSIS-compliant Standard Peripheral Libraries, ...
3
votes
2answers
242 views

Task switching on Cortext-M3 crashes after IRQ

I've used an exokernel model for my ARM OS. When a task wants to read from a UART it calls a library function, which, if there's no data, makes a SVC call to block the task (which causes the kernel to ...
3
votes
1answer
2k views

uCLinux footprint breakdown?

Another question I have asked made me ask this question.. The previous question was about fitting Linux into Cortex M3. A few well answers proved that it is not feasible. SOmebody suggested ucLinux. I ...
3
votes
0answers
152 views

Interfacing LPC1343 with Compact Flash [closed]

I am interfacing Compact Flash with LPC1343. Which is better- 16 bit data and 3 bit addressing or 8 bit data and 8 bit addressing? Anyone please suggest.
2
votes
2answers
4k views

What does the tamper button on my STM3220G-EVAL board do?

Reading through the reference manual of the STM3220G-EVAL development board (an ARM Cortex-M3 dev/eval board) I see that it has a "tamper button", also weirdly referred to as an "anti-tamper button". ...
2
votes
2answers
2k views

What does 0x0800f298 in ?? () mean?

I'm using GDB to debug a program for a Cortex M3. In the functions where the program crashes, when I execute line by line (using n), I eventually get: ...
2
votes
2answers
360 views

Load and store CPU registers in application context

I just recently started working with a bare STM32F103C8T6 (an ARM Cortex M3) and ran into some difficulties. I have set up a SysTick_Handler to switch the current ...
2
votes
2answers
6k views

STM32F103, Having trouble nesting interrupts

I'm trying to interrupt into a USART handler from inside an RTC_Alarm handler, but it doesn't work. I have set the NVIC: ...
2
votes
1answer
4k views

Clearing lockup after double fault

I'm debugging an STM32 with gdb. For some reason my program crashes, and gdb gives the following. Note: automatically using hardware breakpoints for read-only addresses. stm32f2xxx.cpu -- ...
2
votes
4answers
153 views

Cortex M3 reset handler with vector table relocation

I have a system with an STM32F103, which has a bootloader and a main app. Now, the main app is offset from the beginning of the flash to make room for the bootloader, and on cold boot the firmware is ...
2
votes
1answer
2k views

differences between privileged mode and unprivileged mode in the RTX RTOS

As i said in the title what's differences between privileged mode and unprivileged mode in the RTX RTOS? And why in privileged mode threads has allowed full access to the cortex M processor?
2
votes
1answer
134 views

Basic idea of color look up table

I'm driving an ILI9230 LCD 320*240 16bit interface, with a framebuffer of 250*200 and I want to drive it as 4bit. so I built a loook up color table like that: ...
2
votes
3answers
7k views

Faster IO on ARM Cortex-M3 (Sam3x8e) than PIO_SODR and PIO_CODR?

I have a very simple C program that toggles a pin on a Cortex-M3 board (SAM3X8E) with a 84MHz clock speed. I built this using Atmel Studio 6.1. ...
2
votes
1answer
526 views

LPC1788 external interrupt with CMSIS

There was a wide GPIO functions in the CMSIS initial versions which made easy setting and initialization of interrupts,like: ...
2
votes
1answer
22k views

Understanding Timers, Counters and Prescaler Registers on the STM32

So I'm trying to set up a very simple periodic interrupt on my STM32VL-Discovery board using the libopencm3 libraries on linux. I've looked at the documentation and I just want to verify with ...
2
votes
2answers
3k views

How do I call a C function in another module from inline assembler in IAR EWARM?

I don't know if this is recommended or not but I am sure someone will give me a stern warning if not. I have posted a duplicate question in stackoverflow, however this may be just as appropriate here ...