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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2
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3answers
509 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
21 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 ...
0
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0answers
12 views

How are Arduino's OSH if Atmel AVR is proprietary? [migrated]

I keep reading how Arduinos are "open source", but my understanding of OSH is that all its components must be open source. Arduino uses an Atmel AVR CPU - but Googling this shows the Atmel is ...
0
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2answers
46 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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2answers
57 views

Weighing machine using AVR [closed]

For my project I was thinking of designing a digital weighing machine using AVR micro controller but I am stuck having no luck in finding any articles from the web. So please help me in the design ...
0
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0answers
22 views

Driving conveyor belts using arduino unos [migrated]

We are planning to drive conveyor belts with arduino unos using stepper motors. We are planning to use easy drivers, so that we control atleast 3motors with one uno. Currently we are still at an ...
1
vote
1answer
59 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, ...
0
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0answers
31 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, ...
0
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3answers
115 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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0answers
18 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 ...
1
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1answer
36 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 ...
0
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2answers
56 views

Compiler complaining about type declaration in function prototype

This is a library for motor control I am writing to use with the Sparkfun Monster Moto Shield. I have stared at this code for hours, looking for a stray or missing semicolon, or whatever might be ...
0
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0answers
58 views

SIM card used as secure storage with AVR

I would like to use a regular SIM card to store an AES key to be used by an AVR micro-controller. I think that a SIM is secure enough (isn't it?). My problem is that I can find nothing about ...
2
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0answers
22 views

How do I reset an AVR's SPI read shift register?

I'm using an AVR chip (i.e. Arduino Uno) to monitor SPI traffic on an external device and I'm running into a problem due to the fact that the external device periodically restarts itself (by design). ...
0
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2answers
93 views

Do AVR can do anything ARM can't? [closed]

Do AVR (mega, xmega, AVR32) has any capability that ARM based MCUs don't have? or can achieve particular purpose cheaper or easier? Simply, do AVR worth learning?
-4
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1answer
132 views

What is the best suggested way to amplify the voltage and ampere of a signal coming out of a microcontroller and keep wave form as it is?

I am generating semi-pure sine wave voltage signal out of an AVR microcontroller. The thing is I want to amplify this signal (power amplification [voltage and current]) with keeping wave form as ...
-1
votes
1answer
75 views

atmega32 is working OK but atmega32A is NOT!

I have a board which there is an LCD on it and I want to show some lines in the LCD. I have a broken-pin Atmega32 which the broken pins didn't used for LCD, I have written a simple code which just ...
1
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1answer
146 views

Why do we need pull-up resistors or tri state pins for AVR external interrupts?

Let's say we need to write a program for ATmega32, that reacts to an external interrupt(INT0) through the pin D2. The interrupt is to happen during the falling edge of the signal. I noticed it in the ...
0
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0answers
30 views

How to connect a large exisiting code (some simulator) to the AVR Studio Simulator?

Context I am working on a brushless DC motor controller project. And I would like to verify that the interrupt timings make sense in simulation before downloading my code to the board. Challenge ...
0
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0answers
36 views

AVR ADC invalid conversion result

My circuit works very strange. Can you help me please? Parameters: ATMEGA32A-PU JTAG ICE3 3.3 VCC 8MHz internal osc as clock AVCC connected to VCC AREF connected to GND through 100n capacitor ...
0
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1answer
62 views

Where is a good place to start learning about electrical engineering for AVR stuff? [closed]

Can someone point me to a really good tutorial on electrical engineering, mainly avr stuff. I have looked at alot and none in my opinion really give a complete idiot like my self a good place to ...
0
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0answers
65 views

AVR USB by atmega8a in linux

Im using linux ,I made AVR USB by atmega8a everything is correct in micro and pc ,I can led off and and on but ,I have problem i can’t do this by usb cable (error : Could not find USB device!),I’m ...
0
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0answers
69 views

AVR - Simple(st) serial port programmer

As I'm just getting started with learning anything about microcontrollers, I started from making a very, very simple LPT port programmer (...I think it was just about 4 resistors). It worked well with ...
1
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1answer
91 views

Uart serial communication failing to echo back Atmega16a

I am new to the avr (8bit uc) and recently I ran into a problem using serial communication (uart) with PC. Microcontroller fails to responsd in putty terminal where it should echo back whatever I ...
0
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1answer
29 views

How to Monitoring the lines between an Atmega8 and a LCD using Atmega32

I have a device that it use an Atmega8 to send some data to a 2*8 character LCD. the LCD has 8 pins and the pins are as below from left to right: DB7 | DB6 | DB5 | DB4 | En(Clock) | RS | VDD | VFF I ...
0
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1answer
62 views

What are these unpopulated holes on the Arduino Leonardo?

None of the pinouts online mention these holes next to the power barrel and LEDs. Are they connected to anything?
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0answers
23 views

Recovering fuse bits Atmega128RFA1

I am using an ATmega128RFA1 for senior design. I ran the following avrdude command to set the appropriate fuse bits to use the external clock, however it failed and the high byte of the fuse bits was ...
2
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1answer
75 views

Setting port in main loop causes ISR to starve

The example code initializes an asynchronous timer that is fired every second sets two ports as outputs (PA4, PA6 - LEDs connected) the timer ISR toggles pin PA4 permanently sets pin PA6 to 1 in the ...
0
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1answer
98 views

Two different MCU , different output but none was right?

I write this simple code to check my new burner : #include<avr/io.h> void main(void) { DDRC = 0xFF; //high pins PORTC=0x00; while(1) { PORTC=0xFF; } } ...
0
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1answer
77 views

avrdude: ser_open(): can't open device “usb”: The system cannot find the file specified

I'm using an AVRISP mkII programmer to flash an Atmega 328p MCU. Not an Arduino, this is my design. I'm using avrdude which came with WinAVR. I don't have Atmel studio installed, and I'm using Windows ...
2
votes
1answer
83 views

MicroSD card SPI with ATmega32 [closed]

I want to communicate with a microSD card with an ATmega32 using SPI. I make a simple SPI loopback, and it works fine. Now, how can I communicate with the microSD card to write and read simple bytes ...
3
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2answers
51 views

Low power strategy for dealing with spontainious bit flips durring sleep on AVR 8-bit?

I am designing a ATTINY-based circuit that is intended to run unattended for very long periods of time on a very small battery. The device spends almost all of its time in deep sleep, and only wakes ...
5
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6answers
459 views

WLCSP MCU's - what hardware is needed for programming these tiny chips?

I just received my DigiKey order of some Atmel ATTiny4 MCU's from DigiKey. I wanted to tinker with one of the smallest MCU's I could find, and this was one of them. It is, in fact, so small because ...
1
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1answer
47 views

Learning AVR XMEGA

I am trying to learn how to program the AVR XMEGA by using the XMEGA-A1 Xplained kit with a JTAGICE3 programmer. I am going through the Xmega Basics pdf (link). In one of the instructions I am told ...
1
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1answer
69 views

Is it possible to program AVR microcontrollers using USB-UART converter instead od USBasp?

Is it possible to program an AVR microcontroller (e.g. Atmega328P) using a USB-UART converter like this one: Instead of a usual USBasp ISP programmer: ? If yes, is the procedure the same as in ...
0
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0answers
54 views

ATmega PWM frequency resolution

I am using an ATmega328 for generating a PWM signal. But I need a specific frequency. So I tried to use "PWM Phase Correct" mode (mode 10) for Timer 1. It says, the TOP value should be ICR1. It ...
1
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0answers
58 views

Moving from Arduino to ARM - what should I be considering? [duplicate]

I have a ton of experience working with the Arduino, and I'll say I'm an intermediate in straight C++ AVR and PIC applications. I'm now working on a project on top of an Atmega1284P that is running ...
0
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0answers
34 views

AVR chip restarts when RX line connected to a USB-to-serial module

I have an ATmega644 connected to a USB-to-serial module. When I currently have the ATmega TX line connected through and the RX line connected via a switch as follows: simulate this circuit ...
0
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1answer
32 views

Determine the correct capacitors value

what the right way to determine the correct capacitors value needed for a avr-chip with a crystal oscillator? Let say the crystal's load capacitance is: 20pF and i want to use: atmega8-16pu what ...
2
votes
1answer
231 views

Can't modify global variables in interrupt, despite having declared them volatile

I can't seem to get my global variables (low, high) to change inside my interrupt, despite having declared them volatile. Below is my code. I find it strange that I can modify my global variable ...
1
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1answer
51 views

FXOS8700CQ - Arduino core I2C doesn't work, SoftI2C does

I use the Arduino core libraries in my latest project (ATMega328P MCU) I'm trying to talk to an FXOS8700CQ via I2C. Reading register 0x0D should return 0xC7. The typical Arduino Wire library method, ...
0
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0answers
49 views

ATXMega32D4 Two Wire Interface

Lately i have been using ATMega32A and ATMega324PA and learnt various coding techniques in AVR C programming. One such code i wrote is avr_twi.c for communicating with an I2C accelerometer Now i got ...
0
votes
1answer
71 views

1V output only when load is applied?

I'm working with the Teensy++ 2.0 dev. board. It uses the AT90USB1286 8 bit AVR 16 MHz microcontroller. I'm using the microcontroller to drive a small solid state relay. This was just a basic ...
0
votes
2answers
73 views

Getting bottom row of black boxes with LCD Display on atmega32 MCU?

I need some help with this, I am a completely new to programing MCU's but I am trying my best to get this working and I could relay use some help. I am using the Sparkfun Basic 16x2 Character LCD ...
0
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1answer
83 views

Is it possible for a Teensy 3.1 microcontroller to receive USB keyboard input?

As I've read, it is possible to have the teensy act as a keyboard for a computer. I would like to know if the opposite is possible - can I collect keystrokes through the USB port on the teensy. If ...
0
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2answers
95 views

AVR USART sending garbage

I'm trying to make an ATMega328P to send serial data to my computer and print onto Putty using an arduino board to do the USB to serial conversions. The data that's printed, however is garbage data. ...
1
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1answer
78 views

Why does USB signaling to microcontrollers need resistors

I'm currently trying to make a USB device with the ATMega16U2. On page 187 of the datasheet, there are unspecified resistors between the USB port and the pins of the microcontroller The Arduino Uno ...
0
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1answer
39 views

How to design a 3V3 device to be safely programmed by 5V ISP

I'm designing my first 3V3 circuit with ATmega8. While the uC itself supports both 5V and 3V3, some of components do not. I'm going to place ISP socket on board and I'm wondering how to ensure that a ...
2
votes
1answer
45 views

AVR Assembler Labels

According to doc1022, p. 17 (AVR Assembler User Guide): User defined labels which are given the value of the location counter at the place they appear. My question is, what goes into the opcode ...
0
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0answers
45 views

Atmega 168A fuse programming

I'm currently programming over an Atmega 168A micro controller through a USB Tiny programmer and an ISP interface. The micro controller is set up with an external oscillator and an external person ...