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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ATmega XTAL input capacitance and crystal load capacitance

I need precise low-ppm crystal for my circuit with 8-bit ATMEGA (AT90USB1286). Currently 18pF TXC HC-49 (11.5x5mm) is used. I need also minimize size to reduce potential EMC and PCB. TXC - 7M/B ...
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48 views

No correct signal from ATMEGA162 UART

I got the following circuit: simulate this circuit – Schematic created using CircuitLab And this code to run it: ...
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27 views

I am able to program atmega8 but not atmega16/32

I am new to microcontrollers and am taking it as a hobby. I have USBasp programmer with a 40 pin ZIF socket. I used to program my atmega8 for blinking LED's and other purposes. Now I am working with ...
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35 views

ATmega 1284P lockup or stuck in reset after lightening storm, then fully recovers. How to prevent it?

I have a custom Arduino based data collection system which has been running happily, reporting data over a cellular connection on solar power for a few months. After a lightening storm it stopped ...
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3answers
452 views

What does the T symbol signify in electrical diagrams?

I'm trying to connect to my atmega1284rfr2 using the basic application circuit in their datasheet. The red lines and letters are my own annotations. I'm having trouble understanding what all the ...
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34 views

Programming Atmega8 with AVRISP mkII Error ispProgramMem

If I go to Tools > Device Programming in AVRStudio 6.0 to program the Atmega8 everything is working fine. I've set the ISP frequency to 1 MHz and checked the ...
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46 views

Controlling AC devices using ATmega8

I have an microcontroller ATmega8, TRIAC MOC3083 and thyristor M166P. I need to develop and device which will turn on/off lamp(220V). But while I'm developing I don't want work with AC 220V now, DC ...
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64 views

Playing sounds on an AVR MCU [closed]

I never had to deal with sound and I am pretty sure some of you guys have some experience in that kind of application. My question is more about getting some tips on the different ways to implement ...
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44 views

How to get an ENC28J60 to work?

For starters: Yes I know I'm about to reinvent the wheel with the following task ahead. I want to create my own library for the ENC28J60 for an AVR (ATMEGA1284P). So I've been browsing the net for ...
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87 views

Is it possible to power AVR micro project with just one coin cell battery?

My current project setup is: ATmega328P micro with 32 LEDS driven by 4 8-bit shift registers. System without LEDs draws 20mA of current continuously. With all LEDs lit at the same time, it draws ...
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84 views

Blink LED example does not work

I'm trying to run standard Blink LED example on Atmega8A, but my LED doesn't blink. Here is my circuit: And here is my code: ...
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30 views

How to put these together and do I need a PWM expander?

I'm having here an Atmega8 a PSM42BYGHW603 stepper motor the L298 stepper motor driver ...
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137 views

Removable MCU for a PCB

I am trying to make my first PCB, an would like to program an ATmega328P-PU using my Arduino and a breadboard and transfer it to my printed circuit board. My problem is that either I will make a ...
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53 views

ATmega32U4: no output

I've got a little problem with a board I designed. What I tried to achieve is to control some LEDs with a microcontroller featuring an Arduino bootloader so that you can program it with the Arduino ...
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29 views

AVR Error Handling: I2C, SPI etc

How would one go about handling errors in AVR interfaces that do not specifically provide any acknowledgement scheme? For example, I have an I2C temperature sensor which I poll every 1 hour. So every ...
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56 views

No response from AVR microprocessor while programming

I've been attempting to program a few different micro-controllers using nothing but an FTDI 5V TTL cable and self-written software to bitbang the needed pins on the chips. Until now I had success only ...
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73 views

ATmega8 USB programmer

I bought this USB programmer: USBasp USBISP 3.3V / 5V AVR Programmer USB ATMEGA8 . But I can't understand how to connect it. This picture has got 9 circle inputs and 1 square input but all the ...
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32 views

AVR Flash Writing Error

Got a very strange error while trying to write to ATmega128. Below are the results for 3 cases (using different software but the same USBASP programmer and the same HEX file) Case 1 : AVRDUDESS 2.3: ...
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105 views

Control strong DC motor with microcontroller

Could anyone explain to me what it takes to control a strong DC motor with e.g. an AVR? For example if I have a 24V Motor with 5A or more. How can I build such a circuit? Especially if I want to ...
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95 views

How can I make a latch in AVR without interrupts?

I want to make a simple circuit that when you press a pushbutton, an LED lights up stays lit until the button is pressed again. I haven't delved into interrupts yet on AVR, and was wondering whether ...
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57 views

ATmega128 Extended I/O

This is my fist time working with a "bigger" micro controller, ATmega128. So far I've worked with ATmega328, ATmega8 etc. Reading through the datasheet, I didn't understand couple of points That ...
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113 views

ATtiny External Clock not working

So, I've been wanting to break away from the arduino abstraction for a while now. I made a board that has an ATtiny10 on it with a crystal and an output. I cannot for the life of me understand what ...
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251 views

Why usb to serial port converter can’t program avr microcontroller?

With a serial port or parallel port in pc programming avr microcontroller is very easy and cheap. Problem is, no modern computer come with serial or parallel port. So, usb to serial converter should ...
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120 views

USBasp: Why can I program ATtiny13A but not Atmega8A?

I am using USBasp V 2.0 LC Technology with slow SCK jumper connected. The firmware is not updated. I don’t know if I need to update the firmware. I have successfully programmed ATtiny13A, though ...
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21 views

How to check the source of reset in ATMEGA644p

I am trying to find the source of reset for ATMEGA644p, but I couldn't find the way to do it! MCUCSR gives error in atmel studio as not declared and the datasheet also doesn't have it.
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78 views

Arithmetic Overflow ATmega328

I have written the following function to calculate the current timestamp (since 00h Jan 1 1900). The output I get is: ...
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37 views

Speed and Position Control for high-volt Elektro Motor with AVR

Is there anything that one can purchase to control speed and position of a high voltage electro motor? I am quite a bit of a noob at this but I could think of a circuit using photo-sensors or ...
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61 views

AVR - ATmega16 - Timer config

Trying to figure out the timer setup in Atmel Studio 6 for an ATmega16 microcontroller. And I just don't get it. I am trying to create a TickCount similar to GetTickCount() Retrieves the number of ...
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39 views

Understand Atmega168P Datasheet

I am in the process of reading through the above mentioned doc from here. In page-21, second paragraph in section 8.5 I/O Memory, line 6 is given as below: ...
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49 views

Understanding AVR assembler instruction

From here, I have the following example: ...
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36 views

AVR: Usage of Force Output Compare bits

Currently I'm dealing with Tiny2313 for my project. Timer runs in CTC (WGM12) mode so OCR1A is used to set TOP of the timer. I want to use OCR1B to generate output signal. In documentation is ...
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88 views

EEPROM Write Limit [duplicate]

Just curious as to why do non volatile memories like EEPROM in an AVR have a write limit ? Also is this limit per location/adress in the memory or on the memory as a whole ?
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56 views

Plug-and-play usb-midi controller. How?

I am wondering how plug-and-play usb-midi controllers are created? To the moment I've created a simple midi controller based on Arduino Uno, but I am not able to use it directly. I have to use ...
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104 views

Read DS2401 with ATmega 32 and a 1-Wire protocol

DS2401 is a 64-bit ROM memory that used as a hardware-serial-number. [Datasheet : here] It has only two pin. One of them is ground and one of them is Data/Power pin. So for communicate with this chip ...
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104 views

AVR ATMega I/O pin overcurrent protection

I want protect I/O pin against overcurrent to make circuit more robust. Atmel's AVR040: EMC Design Considerations discusses internal overvoltage protection in General I/O Pin Protection paragraph. But ...
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51 views

Clearing Flag Bits By Writing 1

Most of the interface devices have various flag bits (that can also raise interrupts if that functionality is provided) used to check the status of the device/operation. Usually they are cleared by ...
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123 views

Current draw at digital output pin differences in two equally coded segments -probable cause?

I measured the current output of an Arduino Duemilanove (with an ATmega168) in two cases and found out that the currents differ strongly. The following code creates an output of 72mA at pin 13 ...
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61 views

Simulate DS2401 with ATmega32?

I have a DS2401 and an ATmega32. I can read the its contents with my AVR micro-controller. I want to know, Is it possible to simulate the DS2401 with my ATmega32? I mean is it possible to connect ...
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47 views

One-Wire data transfer with a DS2401 via AVR [closed]

I've an ATMEGA32 and a DS2401 (64 bit ROM - Silicon serial number). I want to read its contents. Can anyone help me giving me a clue, sharing a pdf tutorial link for One-Wire communication or a ...
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44 views

NRF24L01+ IRQ Issue

I am testing the functionality of NRF24L01+ and for my purposes I have configured it as PTX, No Auto ACK. I am able to communicate with the chip just fine and able to configure all the registers ...
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33 views

AVR SPI Issue (No data being received from slave)

I am trying to communicate to NRF24L01+ radio module using SPI on ATMega328. When things did not work out, I started analyzing the SPI signals using my logic analyzer. The SPI it set for 1Mhz, MSB ...
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81 views

AVR Embedded Webserver + Time

I have the task of implementing an embedded webserver (using ATMega328). Broadly, the system would provide the following functionality Allow user to change system parameters using the web interface ...
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95 views

Interrupt Management - Large AVR Projects

This is for the more experienced one's out there. I am currently involved with a large AVR project (using ATMega328) and it's getting confusing with respect to interrupts. The project involves ...
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736 views

Are pointers treated differently in AVR compared to say x86?

Microcontroller: ATtiny13 IDE: Atmel Studio I'm trying to write a Hello World application by writing high to port PB4. This works fine: ...
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63 views

AVR bootloader restarts on interrupt

For a quite while, I've been using an avr ATmega324PA controller and Atmel studio to write the programs. we wrote a TCP bootloader. It works fine without any interrupt. Later we did add an external ...
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76 views

AVR USART Garbage Data

I have been having issues with my AVR USART. Using a PL2303 USB adapter with the following connections to the AVR What I am seeing is Garbage data (mostly of 0xFF or 0xF7 or 0xE7) even when the ...
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71 views

Ethernet chip with integrated tcp/ip stack [closed]

I would like to ask what Ethernet chips are popular for an embedded webserver project. Features needed ... integrated tcp/ip stack support ntp protocol php support Basically the main purpose of ...
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3answers
361 views

What is an easy way to program an ATtiny microcontroller in C without an ISP?

I understand the "most raw" method to program an AVR microcontroller is probably with an ISP such as the AVRISP mkII. However, I'm after a method that doesn't involve me having to purchase a $40 tool ...
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Why am I getting verification errors with avrude?

I am constantly getting verification errors with avrdude and atmega168. I googled a lot, but everyone is getting them at first byte, whereas I am getting them at random bytes: ...
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55 views

AVR SPI Loopback test

I would like to do a loopback test on my ATMega328 to ensure that the code I am writing (while learning SPI) is working fine. To do this I would place a jumper between the MOSI and MISO pins. What ...