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Questions tagged [avr]

AVR is the family of microcontrollers used in Arduino boards.

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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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154 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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3k 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). ...
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127 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 ...
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1answer
243 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
1k 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 ...
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1answer
470 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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2answers
6k 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
1k 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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226 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 ...
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1answer
66 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
520 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. ...
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1answer
118 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
717 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
363 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
4k 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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157 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
439 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
168 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
468 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
2k 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
2k 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
285 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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153 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
841 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(): ...
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611 views

Including an arduino library in Eclipse Neon (undefined reference to)

I'm trying for the first time to use Arduino Libraries (Servo.h & Servo.cpp in this case) in Eclipse IDE. So far I've managed to compile and run Arduino code using this tutorial (I suppose many ...
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1answer
82 views

Can't send Data to LCD1602 with I2C

I've been doing fine with my LCD1602 I2C configuration but I discovered that command and data functions are the same even though I change the RS command/data bit, but the result is the same. This is ...
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3answers
405 views

More speed from ATMEGA328 Internal Clock

I have a board that is designed and produced. It was designed to use an Atmega328 with the internal clock. There is no space on the board to place an external clock. After completing these and testing ...
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3answers
599 views

Shift Register on ATMEGA328p

I want to learn more about the shiftout function used with Arduinos and used the implementation with my ATMEGA328p. The Setup This is the original shiftout function used in Arduino Programming, ...
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1answer
582 views

Attiny85 not recognized at windows startup

I'm using an Attiny85 to interact with a computer using an USB connection, and everything works fine except when I restart my computer and the Attiny85 is connected. When Windows end to boot up the ...
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1answer
176 views

I2C begginer with I/O expander with mega328p C code

I've just started with the I2C protocol. I read about it in the datasheet, other documents, blogs and videos. So, I started to develop my code and I think I did my first success, I succeeded to send ...
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1answer
820 views

How to find the pin map for the LCD 1602 I2C adapter module?

I'm working with I2C to work with my LCD 1602 and the I2C adapter. This module has 16 pins and I don't know how to communicate with it. I2C sends 8-bit packets. What are the commands to deal with ...
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1answer
570 views

Building Custom Bootloaders

Recently I was checking out the Atmel's AVR series and I found the Atmega328PB. I am really familiar with Arduino's environment. So I thought if somehow we could bootloader it with Arduino bootloader. ...
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1answer
134 views

Is setting AVR TWCR for mega328p TWEN in each function necessary?

I found this useful website explaining for to configure and implement the TWI for mega328p, but what I found not so obvious is that in the website they set TWEN in every function, while in the ...
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22 views

Programming ATUC256L4U using only Arduino ISP

I heard that you can program any AVR Microcontroller by just using Arduino ISP Can I program ATUC256L4U by just hooking it up to Arduino ISP and Caps, Crystals and etc. Or do I need to do some more ...
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1answer
29 views

What if I detach AVR micro controller from the Arduino Board after uploading program?

What if I detach AVR microcontroller from the Arduino Board after uploading program? Does the microcontroller still have the program on it? Or the program will be deleted? On the board where does ...
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1answer
344 views

TWI Wire.setClock() on non arduino AVR MCU issue

Using an Atmega168P - programmed by means of avrdude with the .hex file generated by Arduino IDE. The following code sets the 8 MHz Atmega's TWI interface to just 15.625 kHz: Wire.begin(); // ...
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1answer
162 views

Arduino IDE compiling for non-arduino AVR boards

Using: Arduino IDE 1.8.2 the board manager from https://mcudude.github.io/MiniCore/package_MCUdude_MiniCore_index.json an ATmega168P MCU in TQFP I was able to run my code successfully by modifying ...
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3answers
2k views

Can I compile a sketch for my attiny85 without an arduino board?

I have a lot of Raspberry Pi's laying around, so I want to use those to program my attiny85 chips. The problem is that most of the code examples, libraries, and documentation out there assume you're ...
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1answer
1k views

Arduino EEPROM retains old data after flashing with a new program

I have a custom 5V 16Mhz Arduino Uno (a breadboard Uno of sorts) that runs the grbl firmware. After the initial flashing I can see all the settings (through the serial monitor) and everything works. ...
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3answers
516 views

Arduino UNO USART problems

I need to send 6 bytes value from Arduino UNO to the actuator using serial port in order to make it extends. I have added a button to send the data. For example, 0 20 1 1 0 0. The communication ...
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1answer
3k views

How does avrdude burn a bootloader much quicker than the Arduino IDE?

To burn a bootloader to the Arduino Micro (ATMega32u4), I'm using an Arduino Uno with the ArduinoISP program uploaded to it. 1st case: Arduino IDE Very straightforward, using the ArduinoISP sketch ...
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1answer
52 views

Pllzz help me with this error i m using Arduino uno r3 on win 10 [closed]

Error picture on screen jdhvdixbdicjdhdojchdishcishcheoshcjd
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1answer
1k views

What Are The Differences Between Arduino Language and Standard C for MCU? [duplicate]

What the differences between Arduino language and standard C used for MCU programming (like AVR).I heard Arduino language is C.What happen if i use Arduino language with bare-bones AVR chips.Or with ...
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1answer
4k views

My Digispark board won't show up in Ports tab in Arduino IDE (OSX)

I bought a Digistump/Digispark board online and when i received it, I plugged it into my iMac to see if it works. I went to the apple in the top left corner and clicked "About this Mac". Then I ...
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1answer
53 views

A confusion with setting timers

I was reading a tutorial on timers. My aim is to generate 16MHz pulse output from the pin 8. Here is the code I modified from the tutorial (I use Arduino's ATmega328P): #include <avr/io.h> #...
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1answer
345 views

A question on physical locations of the registers in ATmega328P

When I read about registers I always encounter the following illustration: So there are 32 registers in the above diagram. They are processor registers. But in the data-sheet of ATmega328P at page ...
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3answers
413 views

Problem with transmitting 2 byte data in correct way

I'm using Atmel Studio with Atmega328P. I'm trying to send the decimal number 876 continuously from the micro-controller. This was just to learn. To send 876 I need two bytes which is: 0x036C = ...
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3answers
95 views

Problems creating 10Hz pulse wave

I'm trying to make a 10Hz pulse wave output at Arduino's pin 9 by using the following code I wrote: #define F_CPU 16000000UL #include <avr/io.h> //Defines pins, ports, etc. #include <util/...
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3answers
178 views

Can I port a project built on Arduino Uno to a standalone ATmega328 using the exact same code?

I'm building an IoT power usage monitor in which the data is logged using a RTC and an SD card module and a web app hosted on an ESP8266 gives access to this data. My question is can I use the exact ...