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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controlling USB game device from AVR

I have this missile launcher. I successfully wrote Python script to handle it from my linux. My next step is to operate it from AVR (Atmega328). Is it possible to control USB device from AVR? It is ...
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1answer
74 views

Software Serial alternative with AVR (Two Serial/UART ports in atmega328p)

Arduino pins can be used as UART using the library SoftwareSerial.h Is there any alternative ...
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1answer
55 views

How to program a microcontroller over another microcontroller?

I am currently working on a project that requires two separate microcontroller to work together, but since I am still working on the project I generally need to update their programs. I couldn't find ...
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1answer
247 views
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41 views

CS/SS pin configuration

I am using an ATtiny861a and I want to enable it to use SPI. In doing this I need to assign not one, but two CS/SS pins in order to communicate with a radio and an external memory. Does the CS/SS pin ...
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1answer
31 views

CC2520/ATtiny861A pin configuration

I am looking to hook up a radio with an ATtiny861A microcontroller. The radio that I will be using is the CC2520 from Texas Instruments. The RESETn pin(on the CC2520) will allow me to put my circuit ...
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1answer
40 views

What is holding the SS pin high in SPI master mode on AVRs?

A typical AVR datasheet contains the following example of an SPI Master mode configuration (here from page 164 of the ATmega128/L datasheet): ...
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1answer
57 views

SPI communication with multiple slaves

I am working on a project that is using an ATtiny861A and this only has one SPI. If I want to hook up a radio and an external memory to the same SPI, will there be an issue sending data from the ...
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1answer
29 views

AVR global variable modified by interrupt not persistant

Using an ATmega328p, I'm running into a problem when I make an interrupt (INT0 or INT1) active, the code will execute just fine (MusicOnLed and FadeOnLed functions will execute), however as soon as I ...
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1answer
50 views

Why the led is blinking instead of keeping on atmega8

I wrote a very simple sample code into my atmega8 via avrstudio here it is: ...
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1answer
18 views

WS2811 RGB LED Strip Timing Issue

I recently purchased addressable RGB LED strips based on the WS2811 chip. These strips have a single data + clock line that uses NRZ style encoding to distinguish between a 1 and 0. The datasheet for ...
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2answers
53 views

Alternatives to Arduino for controlling LED's and Audio files? [closed]

Simple Alternatives to Arduino Has anyone used these different boards? If so, what did you use them for and why? Which are appropriate for controlling LED's and playing audio files? I'm looking ...
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166 views
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Is it possible to set a breakpoint in AVR Studio in files other than the one where the main() function is?

If I have a project with more than one translation unit, AVR Studio only allows me to set breakpoints in the main c file. It doesn't matter if I include the other files directly by ...
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2answers
73 views

How to determine the end of data received by USART?

I am receiving some strings from UART in AVR. Strings are chaotic, not deterministic. It also includes new line \n and carriage return \r characters that's why I couldn't find a solution including ...
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1answer
34 views

Atmega2560 Usart Interrupt problem

When I send any data from serial port, RX pins are flashing but ISR is not running. Here is my code. ...
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24 views

Sending data from web app to arduino powered virtual doorman [closed]

I do not know much about electronics but am looking to learn more. I have a small project I have completed a good portion of that I now need some electronic expertise to determine if what I am trying ...
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1answer
40 views

Atmega328 fast PWM (mode 7) of timer 0 not working as expected

I am blinking an LED on PORTB5 using timer 0 in mode 7. The time between blinks is computed as $$ \frac{(\text{OCROA}+1) \times \text{prescaler} \times \text{timerCount}}{\text{FCPU}} $$ ...
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2answers
183 views

Interrupt fails to change variable, how so?

Problem was virtually undebuggable, the interrupt that was changing a variable would randomly fail to do so, with no apparent pattern; within interrupt code variable would change but outside of it the ...
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2answers
94 views

ADC calibration in ATTiny88

I'm writing an embedded app for ATtiny88 - one of its task is to measure voltages of serial connected two 12 V car batteries. The microcontroller is powered from around 4.5-5 V (LM317), measured ...
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2answers
92 views

How to request “GET” from an ASP.NET website using ESP8266?

AT+CIPSTART="TCP","zgrdataserver.com.azhar.arvixe.com",80 OK, works. AT+CIPSEND=92 The response is ">". Works fine, but ...
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13 views

Adding Atmel QTouch to an existing project for an AVR that isn't supoprted by Qtouch Composer

The QTouch Library supports many devices http://www.atmel.com/Images/QTouch_Library_Selection_Guide.xls QTouch Composer, part of Atmel Studio, however, supports only a small subset of those. I've ...
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1answer
104 views

My For loop isn't exiting and I don't know why

I'm programming an ATMEGA328p on a breadboard and using an arduino board to do the USB to Serial conversion. Part of some code I'm writing involves a for loop that is being used to take the 8 bit ...
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29 views
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3answers
60 views

Can I program a 3.3V ATmega MCU with 5V programmer (USBasp)?

short question: I have ATMega8A at 3.3V I have USBasp programmer at 5V (from USB port) Can I program this AVR with this programmer directly? Well, ATMega can stand 5V but it's powered with 3.3V so ...
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1answer
63 views

LED can't stop blinking (AVR-C)

So here is the basis of my code, I have an array of different instructions for the prescribed LEDs to follow. The led will blink for the prescribed number of times in an interrupt before they stop ...
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3answers
891 views

Non-manufacturer microcontroller selection site?

I'm looking for a site which I can input my desired micro-controller characteristics. I have found the manufacturer websites...but those will only show their micro-controllers. I.E. there's a site ...
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4answers
83 views

ATmega328p and USB conection to PC

I posted the same question on StackOverflow and I was redirected here. For my project I need to be able to program the eeprom of an Atmega 328p via an USB to PC. I tried to incorporate an USBasp ...
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1answer
24 views

AVR Timer1 OCR1A controls TIMER1_COMPB_vect interrupt!

I was struggling with timer interrupts in my project. I couldn't make it work properly. So I decided writing a simple code and I saw a very interesting case. ...
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1answer
47 views

SLEEP_MODE_ADC interfering with USART (and beep)

On an AVR ATmega328P, once per second I am doing 3 AD conversions immediately following each other with 16x oversampling using SLEEP_MODE_ADC like this: ...
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1answer
83 views

Sending info from python to avr-c

okay so my situation is that i am working an avr chip which is the atmega 328p and what i want to do is i want to lets say have a user input in python lets say the user types in a string and from ...
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1answer
16 views

AVR ATmega644p: can't clear OC0A pin on CTC mode

I made an IR blaster for controlling TV (on and off) based on ATmega644p. I am using Timer0 in CTC mode to generate 38kHz waveform. This is the code: ...
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2answers
61 views

AtTiny45 read lag?

I have set up 2 AtTiny45 setup like this (The left one is also connected to power): from which one (the left one) is generating a signal which is (when measured) looking like this: The second one ...
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3answers
57 views

How to send string in serial communication in AVR-C

So as the title states, instead of sending a byte of information at a time, I would like to be able to send a whole string. What I tried to do was that I tried to put the user input in an array and ...
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13 views

Does the ability to program a servo imply that the Lock Bits were not set on a Atmega48?

I'm wondering is how this servo programming business works: The servo (HS7980) has an Atmega48 chip and uses a proprietary protocol for programming so it seems pretty likely they lock it to prevent ...
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1answer
57 views

Emulating greyscale on a 1-bit LCD

I have an LCD (the DOG-M 102x64, with a uc1701 controller) that I am driving (over SPI, but that's somewhat irrelevant) from an AVR (ATMega16 @ 8 MHz) - all in all, a fairly low spec'd screen with a ...
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1answer
45 views

toggling a pin using the hardware compare feature of timer1 AVR

This link - says: "In CTC mode, you can also trigger interrupts, but it is also possible to not use interrupts and still toggle an output pin. Using it this way, the functionality occurs ...
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1answer
70 views

One wire (+GND) serial communication. How to have a correct coupling?

I'm a firmware developer more than a hardware designer. I've a doubt about an idea of mine. I want to obtain serial communication between eight ATtiny85 (slaves) and an ATmega168 (master - It might ...
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1answer
47 views

UART: two transmitters, single slave

simulate this circuit – Schematic created using CircuitLab My circuit is shown above - where I have the TXD pin of an ATMEGA connected to the RXD pin of a BT slave. Both devices operate ...
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2answers
158 views

How to control 200 relays with micro controller?

I want to control 200 relays, I want to use AVR controller. Because I am out of pins, I was thinking of connecting the micro controller (for routines and such things) to a FPGA and use the output of ...
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2answers
68 views

AVR programmer power supply (ISP ATMEGA16 ATmega32 Minimum Board)

In description of an AVR programmer, it is talked about everything except for the input voltage and how to turn it on. How much voltage should I apply to it? Somewhere it has mentioned "DC-005 Power ...
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1answer
38 views

Valid use of ISR_NOBLOCK

I am using two timer interrupts: TIMER0_OVF triggered every 12 ms, with its ISR only polling a pin, conditionally setting a flag and incrementing a value, so it ...
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3answers
81 views

AVR-C turning led off after number of blinks with interrupts

so what I am trying to do is that I am trying to make the led blink for a certain number of times before it turns off. I want to avoid using delays so I tried utilizing the interrupt and I also used a ...
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1answer
49 views

Migrating from the ATMEGA8 to the ATMEGA88PB

I have a simple project that only requires the UART i/f of ATMEGA8, running off 8MHZ internal RC oscillator. I have the DIP package version of ATMEGA8 and things are working fine. I have code compiled ...
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1answer
60 views

Attiny10 not triggering timer overflow interrupt while simulation (Atmel Studio 6)

I have problems simulating the timer overflow in Atmel Studio 6. The code is for an Attiny10 and looks like below. As far as I know I set all the neccessary bits to enable the counter (which works in ...
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1answer
63 views

High frequency SPI-like communication: is there any hardware allowing software tweaking?

I will need to communicate with a device using serial protocol mostly similar to SPI but with several changes: Data packet can has any bit length (e.g. 35 bits) Stop sequence formed by lack of ...
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1answer
54 views

File transfer between two gsm modem

I'm wanting to build a system that will store value on a SD card to form .CSV file , that this is not a problem. There will be about 1000 value recorded daily.I'm wanting to send this values to a pc ...
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4answers
124 views

AVR [ Why IO Registers have IO addresses and SRAM Adresses ]

I was checking ATMEGA16 datasheet , and at pg17 I found that there is the IO registers that happen to have " IO addresses and SRAM addresses " , I don't know which we use and why there is two kinds ...
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1answer
52 views

Best way to compare value in register with constant assembly AVR

I am newbie in assembly and AVR, I wonder what is the best way to compare two values like in C ...
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4answers
366 views

Understanding interrupts and software button debounce

I'm quite new to AVR programming (avr-gcc). To react on button-press, I am using a PCINT ISR with the internal pull-up resistor enabled like this: ...
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1answer
70 views

Stop timer set new value and start again AVR (Interrupt)

I have AVR MCU. I am playing with timer now. What I need ? I have timer counting up with some frequency. In each interrupt I am incrementing variable, and somewhere I need to check value of this ...