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Questions tagged [avr]

AVR is the family of microcontrollers used in Arduino boards.

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1answer
33 views

Force TCNT to stay below OCRxA on ATmega328P

I'm using a timer and the TIMERx_COMPA ISR to generate a signal in "the background". This ISR is triggered when the timer reaches a certain value (OCRxA), which in turn can be changed by the user. ...
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1answer
22 views

About possibility of implementing kalman filter on atmega32

I have searched on the internet on how to get Euler angels from IMU measurements,I found that kalman filter and mahony filter are used...kalman filter has a drawback of complex computations,but mahony ...
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1answer
18 views

.elf and .hex equivalency? (code, eeprom, fuses, and lock bits all in one)

I have all configurations (eeprom data, fuses, lockbits) of my ATMega168A together with the code in my C files. The compilation creates an elf file that I use as an all-in-one programming file for ...
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0answers
14 views

Installed configuration won't show up on Board menu

So I was following these instructions on the official site. Download this hardware configuration archive: breadboard-1-6-x.zip, Breadboard1-5-x.zip or Breadboard1-0-x.zip depending on which IDE you ...
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2answers
75 views

AVR software reset without watchdog

I wrote a generic avr program wrapper which already use the watchdog timer to restart - and after the watchdog reset - recover the the bad situation. After this recover process i have to restart the ...
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1answer
36 views

AVR-GCC can't call function located on fixed address

I wrote the following code: #include <avr/io.h> __attribute__((noinline, section(".app_start"))) void app_start() //app_start section starts at 0xFA0 { //register_packet_dispatch(...
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1answer
107 views

Can the IDE handle a 32khz main clock?

I read somewhere that having the main clock be 32768Hz messes not only with micros() and millis(), but with some other stuff too. Is this true? Will I have to forgo the Arduino IDE to program for an ...
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1answer
48 views

Lines not pulsed fast enough (?))

Should this code pulse the PB3 and PB4 pins (MOSI and MISO of an Arduino Uno) at 2ms interval ? #include <avr/io.h> int main(void) { // for (byte i = 0; i < 32; i++) // pinMode(i, ...
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1answer
52 views

noisy output lines when waking up from a sleep

Using code similar to these examples from AVR https://www.microchip.com/webdoc/AVRLibcReferenceManual/group__avr__sleep.html my program causes my Adafruit Feather 32u4 to often sleep. When the ...
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0answers
30 views

Programming ATMEGA328p via AVR Pocket Programmer

I have a ATMEGA328p on a breadboard with the following connections to the 2x3 ICSP connector and its connected to AVR Pocket Programmer. While running AVRDUDE utility, i get the following error, ...
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2answers
308 views

How are errors (not related to syntax) managed in arduino and in the AVR architecture in general?

I was just curious about how the AVR architecture manages errors that would cause a regular desktop program to crash. I'm talking about logical errors for example math problems that are undefined. ...
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1answer
107 views

Trying to run Timer1 in ATmega2560 with assembly

I have a slight problem with Timer1 in arduino (ATmega2560) while coding it in assembly. I try to run the Timer1 in CTC mode - I configure everything well in my opinion, but the TCNT1 just doesn't ...
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2answers
46 views

Why isn't the stack pointer changing in this simple sketch?

I'm playing around with context switching, and my first idea is to play with SP and see how it changes. However, Sp doesn't do what I expect. The sketch is below. I'm using an Uno R3. What I expect ...
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1answer
124 views

Assembly for loop repeating 2 times when it's only suppose to do it once

I'm programming an Arduino Nano so I belive that this question should be qualified for this SE. I am trying to dim up an LED using a for loop in AVR assembly. My problem is that the cycle is ...
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1answer
378 views

Why are Arduino timer registers not 0?

I'm trying to use the timer registers to do some timing on my Arduino Mega 2560. The output of the following code confuses me: void setup () { // Set up serial connection Serial.begin(9600); ...
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1answer
72 views

Arduino and AVR Serial Communication over USB

I have a Arduino Uno Rev3 and I would like to use a AVR development toolchain to write a program that performs serial communication over USB. Doing this using the Arduino IDE is fairly simple: void ...
2
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1answer
348 views

Generating 200 kHz pulse on Arduino Uno in normal mode

I need to obtain 200 kHz from Arduino Uno. I am using Timer0. I have configured it to run in normal mode and the Prescaler is set to clk/8 (the clock frequency of Arduino is 16 MHz). TCNT0 ...
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1answer
109 views

OpenOCD with FT2232H on Arduino Mega (ATmega2560)

I want to do on-chip-debugging on an Arduino Mega. According to its datasheet, the ATmega2560 chip supports JTAG. (IEEE 1149.1 compliant) Can I use a generic FT2232H interface to do on-chip-debugging ...
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0answers
180 views

50% duty cycle on phase-correct PWM on Timer 2

According to Ken Shirrif's article, Ken Shirriff's blog - Secrets of Arduino PWM (and the same article on the Arduino pages - Secrets of Arduino PWM), under the section Varying the timer top limit: ...
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2answers
283 views

How to read OC0A when in CTC (toggle) mode?

I have this code, which puts the Arduino into CTC mode with interrupts, and outputs a square wave on PD6 (OC0A): void setup_timer(double p_ms, double duty){ DDRD |= (1 << 6); // set pin 3 as ...
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2answers
57 views

Help - Atmega328p, converting a PWM servo code from pin9 to pin6

I found a working code that uses pin9 (PB1) on my Arduino for controlling a Servo, but in my project, an ultrasonic sensor is already using that pin/timer. I want to convert the code to use pin6 (PD6),...
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0answers
28 views

Problems using Arduino pcb as ISP with Atmel Studio 7

This issue has been bugging me for the past few days! I have learned a lot with my Arduino and the Arduino IDE over the past few years and decided to learn how to make faster, leaner code. I want to ...
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1answer
81 views

How to stop sending the last received char of UART echo function?

I developed a code for uart based ISR with linear buffers, the problem is that it keep sending the last received char in Arduino IDE. Here's the application code: #include "uart_new.h" void setup() ...
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3answers
585 views

Is it possible to use extra AVR Flash memory as non-volatile EEPROM-like Flash memory storage?

In STM32 microcontrollers it is possible to use a technique that ST calls IAP, or In-Application Programming, in order to write to the Flash memory from your running application. They even have a nice ...
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1answer
133 views

Burn hex with optiLoader

Can optiLoader be used to burn custom hex? For example, there's hex representation stored in optiLoader.ino in image_328, if that value is replaced with content of my pre-compiled hex, should that ...
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0answers
118 views

Standalone Programmer

I am trying to make my small stand-allone programmer to work using this code: https://github.com/adafruit/Standalone-Arduino-AVR-ISP-programmer But when I hookup everything and press button to flash ...
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1answer
148 views

Trying to make sense of the coding style in Arduino libraries. (Particularly the Radiohead library)

I've been using the Arduino IDE for some time now, and I want to shift to coding for the bare AVR microcontroller. So I wanted to begin by porting required arduino libraries to C/C++. I started with ...
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2answers
1k views

sbi() and cli() implementation

I've often seen cli() and sbi() in Arduino code. I usually don't mind them as I know what they do (clear or set the bit given as second argument in the register of the microcontroller given as first). ...
0
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1answer
101 views

parse intel hex into SPI commands for arduino ICSP AVR

I'm attempting to use the arduino as an ICSP AVR to flash hundreds of ATMEGA's 90USB162. I'm having some difficulties when trying to do the actual flashing of the chip. I've go all the wires done ...
0
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1answer
203 views

How to scroll data in LED dot matrix through multiple modules?

I've been struggling in this issue for a long time, I know there are people who have done it. But, I don't have much experience in C to have the skills to design or develop such complicated functions....
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1answer
654 views

How does DDRD |= _BV(PD2) differ from digitalWrite(2,HIGH)?

I'm attempting to copycat the work of Louis Frigon's Toyota Aux Enabler. I have (with a lot of help on this site) managed to begin capturing and understanding messages on the AVC-LAN bus, but I can't ...
1
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1answer
273 views

bit_is_clear(ACSR, ACO) Instead of digital_read(1)==LOW

I am attempting to create a program for the atmega328P which will enable the aux input of a Toyota Corolla stereo. In order to do this, I'm bitbanging AVC LAN. Nearly all of my research comes from ...
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1answer
3k views

Can't burn bootloader through Arduino Nano clone ISP to atmega328p

I'm trying to use a Nano v3 as ISP to program an atmega328p on a board with ISP headers: I followed the instructions under https://www.arduino.cc/en/Tutorial/ArduinoISP which I think have been ...
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2answers
719 views

What's the difference between DDRB and pinMode?

It's my understanding that the following lines are equivalent. They seem to be interchangeable in my sketch: DDRB = 1<<DDB0; and pinMode(0, OUTPUT); Is the first form (DDRB...) setting a ...
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0answers
169 views

Arduino Timer 0 in fast PWM mode and micros()

I have the same problem as described on this topic I needed to set my prescale factor for Timer0 to 1 so I can get a 62.5Khz PWM out of pin 4 My issue is that now the delays() function on my ...
4
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1answer
65 views

How does the microcontroller know which clock to use?

I had seen some tutorials on how to assemble an Arduino on a breadboard. They all just place the external crystal oscillator according to the circuit and then, just burn the bootloader and it starts ...
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1answer
398 views

Arduino program to Blink L LED when input matches a set pattern

I have written a code that is supposed to blink the LED on PB5 pin, when a sequence of input matches a 4 digit password input from a keypad.But the program doesn't appears to be working as expected. ...
0
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1answer
94 views

Equivalent to POSIX mmap() in AVR-libc

Is there an similar function in AVR-libc/Arduino C++ to mmap()? I'm looking for a way to place machine code in memory at runtime and make it executable.
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2answers
424 views

Arduino analogWrite source code explanation

The source code for the analogWrite function looks like this: void analogWrite(uint8_t pin, int val) { ... sbi(TCCRnA, COM0x); OCRnx = val; ... } Where n is which timer (0, 1, 2...) ...
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0answers
285 views

Is it possible to put ATtiny85 to sleep while using TinywireS?

I have an arduino uno as the master I2C device talking to an ATtiny85 as the slave. What I want to do is have the Attiny85 receive a message from the UNO to tell it to power off which will then ...
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2answers
3k views

ATmega328p hangs on USART RX interrupt

I was able to use USART without interrupt driven and it worked perfectly! However, when I tried adding interrupt on USART_RX_vect, the program does not work as expected anymore. Below is my small ...
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0answers
133 views

HMC5883L stops reading when x-axis value get to positive value

I've been looking for a solution for this problem for quite a time I tried different I2C libraries; like, I2C master library using hardware TWI interface * Author: Peter Fleury But the same ...
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2answers
320 views

ATmega328p - ISC00 with INT1?

I was reading about external interrupts using the ATmega328p, and I saw in the chip datasheet under the paragraph "Bits 3:2 – ISC1n: Interrupt Sense Control 1 [n = 1:0]" the following table: Value | ...
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3answers
166 views

What's in an Arduino?

I've been using an Arduino Uno Rev. 3 for a few projects and would like to switch to using a bare Atmega328 chip so I can keep everything on the same board. I've seen the Arduino on breadboard ...
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1answer
356 views

I bought ATmega328p with bootloader and I can't erase it

I bought an online deal which had 10x ATmega328p with bootloader installed. I thought I can erase the bootloader once I got the order (I want to write custom task without a bootloader) but my ...
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2answers
1k views

Do AVR delay functions (_delay_us() and _delay_ms()) use timers?

I'm trying to determine if the AVR delay functions _delay_us() and _delay_ms() use timers in such a way that I can't use those timers for other functionality in my code. If so, what timer does it use? ...
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2answers
1k views

Why we can wake Arduino Uno from sleep using only pin 2?

Can we use other pin as an interrupt to wake Arduino Uno from sleep ?
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2answers
212 views

Is there an ICRn CTC mode interrupt vector?

I can use the CTC waveform generation mode to loop to OCRnA and trigger the corresponding TIMER1_COMPA_vect interrupt. // CTC mode TCCR1A &= ~(1 << WGM10); TCCR1A &= ~(1 << WGM11);...
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2answers
125 views

How do I use an ATMega 328 (not P) chip with an Arduino board?

I just burned the bootloader on an ATMega328 chip and then I put in on the Arduino board. But when I try to upload a program to it, it says programmer not in sync and programmer not responding. For ...
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2answers
709 views

programming arduino in pure c

I'm trying to flash pure c-code to arduino Mega2560 board from linux using avr-gcc & avrdude. Compilation is done , now trying to flash using avr-dude, getting error as "avrdude: stk500_recv(): ...