Questions tagged [avr-gcc]
AVR-GCC is part of the GNU Compiler Collection (GCC) collection of open source compilers that targets the popular AVR microntroller produced by Atmel. It supports both the C and C++ languages.
129 questions
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Does the RFM95 lack a "PayloadReady" timeout interrupt?
I am doing a blocking receive with timeout of a small packet with an RFM95 (FSK mode) and an AVR 8-bit MCU.
Before going to RX mode, both "PayloadReady" and "Timeout" interrupts ...
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SD card and RFM69 radio module on same SPI bus not working?
I am trying to operate a MicroSD card and an RFM69 radio module on the same SPI bus with an AVR 8-bit MCU without success. While the radio module (as usual) works just fine, SD card initialization ...
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Temperature susceptibility, frequency deviation and receiver bandwidth
For fun and to learn, I am writing a simple driver for RFM69HCW radio modules. So far I'm impressed of the high transmission reliability and the long range, but there is one thing I am unsure about.
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Just -65 dBm, are simple wire antennas really that bad?
Short answer: No, they are not. See update below.
I am writing a simple driver with avr-libc for RFM69HCW radio modules. Transmitting and receiving single packages works fine so far.
I don't know much ...
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I2C on ATtiny441
I have a setup where a board (custom-made, designed by us) with an ATmega32U4 communicates via I2C with a second board (also designed by us) with an ATtiny441.
The communication is extremely simple: ...
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154
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Simple I2C communication between two ATmega32U4s -- first transmission works, then it hangs
I have two (different) boards, each based on the ATmega32U4. Both are programmed bare-metal, in C with avr-gcc. Board 1 has USB functionality, using the LUFA library (I started with the USBtoSerial ...
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In AVR-GCC, I am trying to get an atmega328p to sleep and then wake on USART RX, but it locks up
My hardware is pretty straight forward. I have an ATMEGA328P hooked up with an LED on PB5, primarily to troubleshoot, and a wire that connects PD2 (INT0) to PD0 (RX), hoping to use INT0 to wake up the ...
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How to identify all AVR MCUs (ATtiny and ATmega) that feature a factory-programmed unique ID
On Microchip's site, the "parametric search" table for microcontrollers does not have a filter column to select the models that feature a unique ID. Is there a way to list (enumerate) all ...
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Why does compiler optimization flag cause function definitions other than main() to break program in AVR ATMega C code?
I am using avr-gcc and avrdude to write programs onto an ATMega8515 micro-controller. I have got the blinking LED program working without a hitch. However, when I started to use interrupts and ...
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avr-gcc optimization deleting register writes on ATTiny402
I'm using avr-gcc (12.1.0, built with this script: https://github.com/ZakKemble/avr-gcc-build) to compile for the ATtiny402 and encountering problems with code optimization. Specifically, the compiler ...
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How do I measure a pulse width using the ATmega328P interrupts and timers?
I am using an ATmega328P MCU with an 8 MHz internal oscillator. I need to measure the pulse width of an incoming pulse. The frequency of this pulse is approximately 500 Hz. Once every 2 ms, one pulse ...
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AVR-libc `uart_putchar` implementation
In AVR-libc page 143 the implementation of the function uart_putchar() is typical as the following:
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Convert the type of calculation result in if() to uint8_t
I am writing in C using the Atmel Studio (AVR-C.)
I have an if statement:
if( (rxProcessing < (rxWritePos-1) ) )
Where ...
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793
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Atmel SPI "wait for transmission complete" example is wrong?
I am configuring my first SPI transmission on my atmega328p.
Everything seems right (My SPI interrupt ISR(SPI_STC_vect) fires when transmission is done, and I can see all SPI pins on the oscilloscope ...
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Where to find documentation for definitions for AVR programming in C
I wonder if there is a documentation for AVR (I am using C to program) definitions like PIN5_bm or SLEEP_MODE_PWR_DOWN, or if I ...
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Avr-gcc using repeated addition instead of MULU instructions
I recently compiled some C++ code for the ATmega1284P in Atmel Studio and was analyzing the timings of some routines using my scope. To my surprise, a loop I thought I had optimized was taking longer ...
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Why does port B5 on ATMEGA64A-AU malfunction after enabling USART function?
I've wire up ATMEGA64A-AU based on this schematic from here:
I've tried to program a blink on pin B5 which has a LED on it:
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2
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ATmega48PB: wdt in interrupt mode still reset the MCU
I read the datasheet and this question, but there's still something wrong here.
Here my wdt init code:
...
- 1,593
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2
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348
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Changing delay duration in _delay_us() changes code size
I was programming an ATtiny13A when I accidentally noticed that when I change the delay time in _delay_us() my code size changes. Here's the sample code:
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Why the RAM 23lc1024 is not responding or give error?
I interfaced the 23LC1024 RAM module to atmega328. I have coded using embedded c on avr studio. The program flows like one byte is written to the address 0x000000 and Read data from the address ...
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325
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Implementing UART driver with Interrupts and DMA - UART_RXC ISR is executed only first time a character is received
I am using ATxMega 32E5 and my current task is to rewrite existing RS485 driver and use DMA to save in my case
valuable cycles (the speed is going to be multiplied by 8x going from 230k to 2M baudrate)...
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Linking a binary with avr-gcc from object files
I've been able to build and run binaries successfully when I compile and link in one step. However if I try compiling but not linking with the -c option to ...
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Relocation in MPLAB IDE X
I'm writing a bootloader for ATXMEGA256A3U. At page 14, Table 7.1 of the datasheet I know the bootloader address start at 0x20000.
Using AtmelStudio I set in the linker option the following ...
- 1,593
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172
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Buffer exceeding ramsize do not produce error in avr-gcc
In my source code I have tried to allocate a huge buffer exceeding the RAMSIZE value (RAM of my component (ATmega324PB) is 2k).
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3k
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Compress .hex file for micro-controller [closed]
I am currently writing a program in AVR Studio, here is the build *Memory Usage : *
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6k
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Can I use C++ stl in avr-gcc?
I have implemented C++ queue in my codes, those I run on my PC.
Now I'm programming an ATmega128 micro-controller to implement a .c code. Can I use that ...
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190
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413
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avr-gcc keypad interfacing code problem
I have this function to read key press from a 4x3 key-board:
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1
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151
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How to use output PWM in AVR
I have this code to blink an array (8-led) of led one after one:
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313
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Atmega328p ADC - value keeps returning zero when connected
I'm currently try to connect a DS18S20 temperature sensor to the atmega328p. I have wired AVCC and AGRD to the same power rail on my breadboard as normal VCC/GRD and AREF is not connected.
When I try ...
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AVR atmega328p - Can I use port C as digital output pins?
I'm currently trying to connect a 7x5 dot matrix to an AVR ATMega328p. I'm already using port B/D and I would like to use port C so that I have extra output pins. My question is, can I use port C as ...
- 117
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166
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AVR - Timer0 is not firing if INT5 is enabled in EIMSK
I'm using an ATMEGA2560.
Compiler: avr-gcc (AVR_8_bit_GNU_Toolchain_3.4.5_1522) 4.8.1
I have setup TIMER0 for periodic tasks:
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- 1,164
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632
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Issue with SD Card Initialization via SPI: No CMD0 Response
I am working on a project to read files off of SD cards with an xmega128a4u via SPI.
I noticed that some cards initialize without an issue. However, I have two cards that just wont.
As far as I can ...
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233
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(Noob question) Placing parts of a byte in different (parts of) registers
Background: I'm trying to get a gLCD working with an Atmega328p. I got it to work quite easily, but there was one catch: the library that I found, used portB for the datapins. This was unacceptable, ...
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527
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Cannot Disable AVR ATmega32 Watchdog
I'm writing a code to enable and disable the watchdog timer in ATmega32. I'm using the function in the datasheet that disables the wdt. Also, I'm toggling led in the beginning of the code to know if ...
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356
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progmem data array optimized out [closed]
I try to use a ATTiny10 to drive some APA102 LEDs.
The LEDs are arranged in a 5x5 array. To draw something I stored some 'images' in PROGMEM. Program looks like this:
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- 165
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1
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571
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AVR NRF24L01+ No Communication, No IRQ Activity
I've been scratching my head for a few days over getting the NRF24L01+ modules to work on AVRs (ATMega328/p). I followed Gizmosnack's tutorial, not changing very much at all from his code. I've also ...
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5
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Are the AVR GPIO registers used by AVRGCC?
Most (all?) of the AVR family controllers provide some special GPIO registers.
4.8.1 General Purpose I/O Registers
The lowest 16 I/O Memory addresses is reserved for General Purpose I/O Registers. ...
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1k
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AVR SPI slave first byte problem
I have written a simple SPI slave on an ATMEGA328PB. It mostly works, however, I can't seem to get the first byte to be what I want. The difference between the first, second, and all other attempts ...
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1k
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How to create unique label on macro definition on AVR GNU assembler?
On AVR GNU assembler I'm trying to create a label inside a macro definition.
I would like to create a macro, which has a private lable, or unique label inside - just to be able to jump inside macro ...
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734
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SPI between ATmega32 and ATmega328 is not working
I have been trying to accomplish connecting ATmega32 and ATmega328 using SPI
Hardware connections:
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ATTiny414 inline assembly operand constraints for IO pin parameter
I'm trying to use the light_ws2812 library to drive WS2812 LEDs from an ATTiny414.
The core of that library is an inline assembly snippet that bitbangs the serial line. here it is with the timing-nops ...
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AVR-GCC initialization code
Consider the following asm.S
.global main
main:
rjmp main
Compile and dump it with these commands:
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511
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Strange issue with ATTiny10 + avr-gcc: counter used in ISR corrupted by global variables?
I have a very strange issue of a possible memory corruption when using global variables and a timer overflow interrupt on the ATTiny10 (using avr-gcc 4.9.2). I can't make any sense of it but managed ...
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Why does AVR-GCC apparently waste 6 cycles here?
This line...
if (thisWindowsSinceLastFlash <=1 ) {
...complies to this code...
...
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82
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Atmel AT90USBKEY2 delay wrong before dropping power
When I program my AT90USBKEY2 with dfu-programmer, the delays are wrong until I restart the board by unplugging it.
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3
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69
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Is it possible to access semantically connected registers generically?
I have an SPI module which has an initializer function:
...
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2
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859
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Atmega32 ADC Value not accurate
I was trying to simulate on proteus ADC with potentiometer and get the reading to control dc motor with PWM it's working but the problem is the ADC value not accurate. ADCH reach max value before ...
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578
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USART ISR keeps repeating 4 times
Hi,
I'm having a problem with the USART_RX_vect interrupt of the ATMega 328p. The receiving works fine and I'm able to evaluate the sent bits (so it's not due to the baudrate) but everytime I send a ...
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Unexpected bits when shifting out (ATtiny85)
I'm trying to spoof a 433 MHz remote and I have a sequence of 32 bytes that I want to repeatedly shift out to one of ATtiny85's pins. The signal then goes to a cheap Chinese-type 433 Mhz transmitter.
...
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