AVR is a 8- and 32-bit microcontroller core developed by Atmel. AVR was chosen as microcontroller for the popular Arduino SBCs.

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Help Needed To Move From AVR To ARM

I have been working with AVR microcontrollers for the past 2 years and I am now quite comfortable with them. Like most people started with arduino but quickly felt limited by the options it provided ...
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1answer
49 views

voltage dropping when connect pwm output pin of a microcontroller to resistor

I have a circuit that measures the distance to the obstacle then i convert this value to voltage with PWM method . So far everything working properly but voltage dropping when connect pwm output pin ...
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1answer
82 views

Using LEDs to indicate if a toilet is occupied or not?

We have two toilets in our office. I want to setup two LEDs in rooms that show which toilet is occupied and which not. How can I do that?
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2answers
69 views

Why bother using RESET# line on AVR?

I am designing a simple AVR development board based on the ATmega1284-pu and was wondering if there was any reason to use the RESET pin on an ATmega chip to reset it? Why not just cut the power to the ...
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1answer
65 views

Question about MCU's, and Audio Manipulation

Ok, so I've been doing some research trying to find something like an audio MCU\DSP with a built in audio filter; for instance, something that I could manipulate audio with to get a final filtered ...
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3answers
380 views

How to read whole data sent to USART with interrupt?

I am currently able to read byte by byte from USART with this code ...
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1answer
49 views

Hitachi HD44780 LCD works exactly 50% of the time

My Hitachi LCD works 50% of the time. Is it a problem is a deboucing reset button issue on the AVR? Why is this happening? Here's a video of what is happening. This does not happen if I write on the ...
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2answers
33 views

How to detect input voltage change on specific pin of atmega32? DC jack sensing

I am trying to make an LCD circuit that, eventually, will control an amplifier and display data to the user through the LCD. One of the features I want to include is the ability to show if the device ...
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24 views

Is Atmel JTAGICE3 compatible with Ubuntu 14.04?

Is this device compatible with Ubuntu 14.04 http://www.atmel.com/tools/jtagice3.aspx Thanx.
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43 views

What is the key difference of Atmel JTAG ICE mkII, AVRISP mkII, AVR Dragon and Ubuntu compatibility [closed]

I'm a bit confused with those devices. My requirements are: Programming and on-chip debugging of ATMega2560 under the Ubuntu 14.04. Are those suitable for my purposes? What is the difference of ...
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1answer
35 views

AVR's and DC Motors\Servos

I've been browsing around looking for some information on motors\servos and AVR's (my MCU of choice). Motors\servos are in my gray area, meaning I'm still not too into them, but I could do something ...
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3answers
94 views

Automatic agricultural robot using 8051 [closed]

I want to build a automatic agricultural robot for my final year diploma project. The basic idea is to program 8051 to drive the robot in a fixed path in farm for ploughing the farm which i am ...
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1answer
99 views

Atmel printf formatting doesn't work, no formatting does work

We are running an Atmel AVR32 chip on our board, and recently discovered that printf with format/conversion specifiers doesn't work. A regular ...
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2answers
64 views

Shift value to some point in binary number

I wonder if it is possible to do the following. For instance, I have a number 00001110. I am shifting it left. -> 00011100.... But the question is if it possible to start setting value in carry flag ...
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0answers
55 views

Really weird AVR issue

So the other day I was changing some fuse bits on a 324p and screwed up. Well I set up a 88A to act as a clock out. Great. Well I went through 4 different chips, including a 48A, because of some ...
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1answer
38 views

Atmega328 fast PWM (mode 15) on timer 1 not working

I cannot get PWM to work using mode 15 (a fast PWM) of timer 1. It's always giving me a high value of around 4.5V on PORTB2. ...
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1answer
48 views

AVR USB to Serial Converter; Quick Question

I have a TI86 calculator that I've had for over 7 years now. Well I'm letting a lady friend on mine borrow it, and I was going to load it up with some apps for her. And the tradeoff is happening this ...
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2answers
72 views

AVR Rapid Fire Mod… I hit a wall and need some help

Title says it; I'm making a rapid fire mod chip with the 328p family of chips right now (I'm going to scale down to whatever the smallest chip is that will safely hold the final software). I'm a fan ...
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0answers
53 views

Arduino-like boards with other microcontrollers [migrated]

Are there any Arduino-like board designs that are NOT using an AVR chip, but perhaps a chip like the Z80 or the 6502?
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2answers
38 views

XMega Get Clock Speed

I'm doing some debugging on my project and I need to check if I'm setting my external crystal correctly. I have the ability to print out to a serial monitor via usb, is it possible to retrieve the ...
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2answers
296 views

ATTINY85 measuring internal voltage

I'm using an ATTINY85 for a portable application that uses a Lithium-ion battery; therefor I need to monitor the battery voltage so I don't kill the battery. Is there a way to go about this without ...
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1answer
68 views

real time online push button based counting system

I am doing this project: I have 4 inputs. These are push buttons, connected to a microcontroller. Each time a push button is pressed, say for example pushbutton_1 is pressed, the press of a switch ...
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2answers
45 views

Hot ENC28J60 Chip

I need some help figuring out why my ENC28J60 Chip is running hot. This is my first time using the chip and I'm not sure if I have everything right schematic-wise. I'm working on a prototype pcb I ...
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2answers
176 views

AVR and STM32 ARM GPIOs state when IC is unpowered

I'd like to make a device combined two controllers: ATMega64 I already familiar with and ARM Cortex-M0 STM32F051 I'd like to be familiar with. I'd like to directly connect GPIOs of two controllers. I ...
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2answers
64 views

3 channel 10+bit PWM

I am building a controller for RGB LED strip (12V 5m 5050 LED RGB strip with common anode). My current solution uses Arduino Uno with 3x IRFZ44N MOSFETs to power the strip. The solution is partially ...
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1answer
47 views

Burning arduino bootloader with avrdude and AVR dragon on ATmega32U4 failing

I am attempting to burn a bootloader on a ATmega32U4 aka. Arduino Micro which is not succeeding. I am using a AVR Dragon with ISP interface. ...
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1answer
78 views

AVR GCC: How do I improve code optimization

I tried to compile he following C code: period = TCNT0L; period |= ((unsigned int)TCNT0H<<8); The assembler code I'm getting is the following: ...
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2answers
87 views

LMP91000 I2C Write Problem

I've posted this question to TI E2E forum here. I'm cross-posting it here in hopes of casting a broader net. I'm writing an Arduino library for the LMP91000 (github), and I'm apparently having some ...
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2answers
379 views

Is there any DAC that generates a negative voltage or sine wave without offset?

I would like to generate a positive and negative voltage (sine wave without offset) from an AVR microcontroller. I think it needs an external DAC, because the internal ones are not able to generate a ...
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1answer
44 views

Maximum length of Atmel AVR ISP ribbon cable?

I recently picked up a cheap USB based ISP (in-system programmer) for Atmel AVRs. There are two variants of the programming socket that are used with these devices, a 10-pin and a 6-pin. ...
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1answer
54 views

AVR: Timer overflow flag in TIFR [duplicate]

I have a little question about the TOVn flag located in the TIFRn register. The datasheet says, if the ...
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1answer
56 views

How to implement a double buffer using an ARM Cortex M3

I am a total beginner, but I have been working on a project to attempt to build my own microcontroller that outputs basic 2D graphics to an LCD screen. In doing some research as to how this is ...
21
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1answer
601 views

Why does my AVR reset when I call wdt_disable() to try to turn the watchdog timer off?

I am having a problem where executing a disable watchdog sequence on an AVR ATtiny84A is actually resetting the chip even though the timer should have plenty of time left on it. This happens ...
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1answer
27 views

How to select external crystal in atmega162

How to set AVR to select external crystal for clock? A _delay_ms(1000) is producing a quick beep however it should produce 1 sec beep if it is operating on 12Mhz. Could it be done programatically of ...
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3answers
80 views

How can i implement Chirp Signal using C? [closed]

I would like to implement Chirp signal using C code Do you have any idea how can I do it? Edit Goal is to send this signal to an DAC Component (µC intern or external peripheral). But I need fast ...
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1answer
71 views

ATmega162 fuses to select external clock 12Mhz?

Could anyone tell me how I could change the fuse bit, so that my ATmega162 uses 12 MHz external crystal. Once, I made the changes in the AVR fuses wrong the AVR went dead. That is why I need ...
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1answer
28 views

Freq. measurement using pin change interrupt + 4024 counter?

I have an oscillator which I need to measure using an AVR MCU running on an 8MHz Xtal. The output from the oscillator is driving the clock input of a 4024 counter. The freq. range on Q6 (input signal ...
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1answer
67 views

Help understand a simple C code for an atmega16 project [closed]

I just got started with AVR , and I am building a Lan tester for a project My hardware part is done, basically for the send pins I used port A , from A0 to A7 and for the Receiver port C when the ...
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0answers
33 views

RFID interfacing with atmega162 problem

I have interfaced RFID and atmega162 as in picture , but I am getting garbage with blank spaces, hypens on lcd , please see my code and tell me whats could be the problem, Hoping for your help. ...
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19 views

RFId interfacing with atmega162

I am new to programming, I have created a schematic of my project I am not sure it would work or not. I have RFID 125khz - Model no RFID6300. Do this module require MAX232 to be used in between ...
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1answer
77 views

How can the Vss or Vdd pins of a MCU handle sink or source current?

Today I was seeing the datasheet of STM32F103 MCUs and I came across with an interesting thing. assume I have an STM32F103RET6. it's a 64pin MCU of STM32 series. the pinout is this: It has 4 ...
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1answer
71 views

Load capacitance for a microcontroller crystal?

I know there are lots of similar questions on here, but I've read many of them and am still a little confused. I'm a student making a board similar to the Arduino Pro Micro, using a Atmega32U4 ...
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4answers
2k views

Why GCC compiler omitting some code?

I can not understand why GCC compiler cutting out part of my code while it preserve absolutely the same one in the neighborhood? The C code: ...
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1answer
35 views

Buzzer not working with delay avr atmega162

Hi I have got a problem that will be simple to you guys but i am newbie so its difficult for me to get things done correctly, I Have buzzer interfaced with PinC0 of atmega162 , with crystal 12MHz ...
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2answers
54 views

Why prescaler doesn't give 50% duty cycle pulse

I am new to embedded electronics. While reading the datasheet of ATmega328P, I saw this when timers and their timing diagrams were given... I wonder why clk/8 is not of 50% duty cycle...Please help ...
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1answer
70 views

Running a Microcontroller with Selectable Voltage (3.3V/5V)

I'm working on a non-volatile SPI memory chip programmer. My design sends individual data bytes over USB to an MCP2200 (USB to serial converter chip), then the serial data is sent to an ATMega48, ...
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40 views

radxa serial vs atmega serial communication

I want to connect radxa to ATMega8, but I have the following problem: I wrote a simple program for avr to send some characters on serial port. when I connect Rx,Tx to MAX232 and look at hyperterminal, ...
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3answers
154 views

Boost Converter Problems

I'm having trouble with a boost converter I made: it outputs 1.2V with no load and 2.4 with one. I expect to draw 0.25 Amps MAX with Roughly 0.2 Amps continuous. My battery pack is 2P2S NiMH with the ...
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25 views

DAC via I2C: detect error conditions

We are using a MAX517 DAC-device as slave and an ATmega8535 controller as master. Communication errors can be readily detected by comparing (TWSR & 0xF8) with 0x08 for Start, 0x18 for address ...
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1answer
43 views

AVR local and global variable program size

I work on ATmega8 and I need to optimize my code as well as I can, because I am over limit and I saw something surprising. I have a few 8bit integers declared as global variables and a few 8bit ...