Questions tagged [embedded]

An embedded system is a computer system designed to perform one or a few dedicated functions, often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts.

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Necessity of an external watchdog timer

What is the need for an external watchdog timer for a microcontroller? Most of the microcontrollers are designed with an internal watchdog timer. However, in some of the circuits they are using an external watchdog timer (such as PIC16F1824).
Photon001
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How to become an embedded software developer?

I'd like some tips for those who want to become a good embedded software developer or want to improve in this area. What should I need learn about hardware, software? Which books are most recommended? Blogs? In the end, how could I go from a…
Daniel Grillo
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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 modules: - Kernel core - Basic driver set:…
Frank
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Use of global variables in Embedded Systems

I started writing firmware for my product and I'm a rookie here. I went through many articles about not using global variables or functions. Is there any limit for using global variables in an 8 bit system or is it a complete 'No-No'. How should I…
Rookie91
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How to implement critical sections on ARM Cortex A9

I am porting some legacy code from an ARM926 core to CortexA9. This code is baremetal and does not include an OS or standard libraries, all custom. I am having a failure that appears to be related to a race condition that should be prevented by…
CodePoet
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Is SPI safe to be interrupted?

I'm writing to a microSD card from within my firmware, but it's the lowest priority task, so it can be interrupted by other tasks while it's in the middle of reading/writing. Now suppose I communicated with this microSD card using a UART. The…
Maestro
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How does factory reset work?

All embedded devices includes a "Factory reset" option that allows the user to reset his device if something is wrong. I am developing a Firmware on an STM32 board. The firmware includes a boot loader that allows to upgrade the application via UART…
Pryda
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What is bit-banding?

I am reading the ARM Cortex M3 reference manual and the concepts "bit-band", "bit-band region" and "bit-band alias" appear. What is bit-banding?
Randomblue
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Is it possible to make a JTAG interface with an arduino?

If so, could one direct me to a site that tells how to do this? I believe I may have found a way , but I am unsure as to whether or not it would work yet (need to find something to test it on). This question is related to a previous question of mine…
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Why am I Seeing A Weird "Notch" on the Data Line For Some Logical 1s?

I'm attempting to build a Z80 homebrew computer for some retrocomputing fun and to teach myself the basis of electronic design. For proof-of-concept, I've already assembled a basic system on breadboards successfully in the previous weeks. The…
比尔盖子
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Why are some embedded registers password protected?

Some registers on MSP430 devices (and I assume some non-TI chips, but I mostly know MSP430s) have "passwords" that reset the device if software writes to the register without the right password. Why are these registers "password" protected, and why…
Duckrubber27
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Has anyone evaluated NuttX RTOS?

While reading Linux User's Journal today, I stumbled across a little blurb about NuttX RTOS. I checked out their website and was fairly impressed with it's feature set and it's ability to put it in an 8052! I find it interesting that it supports…
Jay Atkinson
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SPI: TI or Motorola mode?

I am programming a Cortex M3 bare-metal to talk with SPI Flash. One of the configuration bits of an SPI control register is FRF (Frame format). It can either be set to SPI Motorola mode (0) or to SPI TI mode (1). (See the ARM reference manual page…
Randomblue
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Where do I start with embedded video?

My boss recently asked me how difficult it would be to design a product that could continually record fairly low quality video and store the last few hours in some form of internal memory. I have never done any development with video before. Where…
PICyourBrain
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Why do I first need to set a value and then direction of the GPIO in an embedded processor?

I have a full time job as a firmware engineer. I've recently been given a task to review GPIO configurations and change the settings as needed. I found a few pins that were incorrectly configured so naturally I reconfigured them, however I was told…
flashburn
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