Questions tagged [avr]
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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Long distance (and I think low frequency) serial communication with Arduino
I need to implement a long distance (up to 15 kilometers) communication between some electronic devices. The devices is some boards on AVR chips with Arduino library and a Raspberry pi as the ...
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1answer
44 views
Avr+code of a burst pulse
How to generate a burst wave with Atmega328??!!
I want to produce like this image that attached below.
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2answers
95 views
Can somebody explain to me thoroughly about DDRx, PORTx, PINx in AVR?
Okay this might be a really dumb question, but I don't really get these 3,
my main confusion is, why we need three of them? Why can't we r/w on port like normal register? (please don't downvote).
And ...
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0answers
22 views
Block reading of SDHC returns 0x00
I have a 4 GB sd card attached via SPI to my XMega MCU and I want to read this card with the USART-SPI interface in SPI mode of the MCU.
So i have this code
SD.c
...
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0answers
60 views
Can't manipulate array with atmega8
I am quite new to AVR programming and I am currently having some troubles with arrays.
I am trying to write an Arduino code that will be run on a Atmega32u4. The goal is to communicate with a AX12-A ...
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1answer
45 views
Confusion on Servo and PWM (AVR)
For reference im using an AVR Atmega 328p, and the servo specs i'll be using says this:
Pulse Cycle: 20 ms (I assume this means the "period")
Pulse Width: 600-2400 µs
So from my understanding, ...
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2answers
199 views
How can I isolate voltage dividers so they aren't interfered with by other parts of the circuit?
I have a small and very basic circuit that PWMs an RGB LED. It has a potentiometer to allow me to set brightness level for night time and a LDR that allows me to detect night time.
I took some ...
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1answer
37 views
EEPROM Interface confusion with Address?
So im researching how to interface with a EEPROM Chip via I2C with an AVR (Still learning a lot of the interfacing).
Anyways, the AT24C16 for instance (or that family of EEPROM) seem pretty popular. ...
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1answer
103 views
On AVR-GCC, how can I find out what statically initialized variable is using up my RAM?
The variable does not show up on the MAP file so it is hard to track it down. I'd rather not have to manually search though all the source code looking for static initializers.
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1answer
110 views
AVR: Pullup vs Pulldown on button input?
So I know the Atmega328p (What im using now) has Pull-up resistors available to be activated. And I know when reading input we could either make a button cause a PIN to go high or low....but is there ...
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1answer
110 views
Protect Code inside Microcontroller
As a preface, what I am asking is highly related to this question. That said, the question linked was asked in 2011 (7 years ago), and I imagine the microcontroller world has changed (at least to ...
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1answer
81 views
Minimal external components for AVR CPU
If I want to program a new AT90USB1286 series chip via the standard 6 pin ISP header, do I need any additional components wired up at all? I'm wondering specifically about the need for a quartz ...
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1answer
28 views
AVR Pin change interrupt: Capacitive Touch Sensor
I'm reading the book: AVR Programming: Learning to Write Software for Hardware by Elliot Williams. In the Interrupt section of the book, there's a small project to make a Capacitive touch sensor.
...
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1answer
59 views
Newbie question: C programing for AVR
The following lines which works exactly opposite to what i'm expecting, would appreciate correcting my understaing:
Button connected with Pin D2 & Led B2:
...
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1answer
50 views
FPGA CAN Bus Test Bed
I don't have familiarity with FPGAs and I haven't used VHDL for 21 years, so starting from scratch.
I am wondering if the following is possible/sensible.
FPGA running n "small" independent ...
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1answer
47 views
SPI: Receiving bytes from slave
For a couple of days I have been learning about SPI and decided to give it a go with 2 small devices.
DEVICE 1: Atmega328p (MASTER)
DEVICE 2: MFRC522 (SLAVE)
As far as I understand:
master sets SS ...
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0answers
12 views
Can't set fusebit on Arduino mega2560
The board came default with lfuse:0xFF hfuse:0xD0 efuse:0xFF
I've been trying several of the programmers that come with Avrdude, but the only one showing some results is -c wiring, the others timeout....
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0answers
32 views
ESP8266 misses some data sent by UART (Interfacing with AVR ATmega32)
First of all, I apologize in case I make some mistakes posting this question. I'm writing from Argentina and I'm trying to send data from ATmega32 (via UART) to ESP8266, and ESP8266 re-transmits this ...
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1answer
40 views
Where MOSI is triggered low or high
Sending and Receiving Data
//Function to send and receive data for both master and slave
...
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0answers
40 views
Increase NPN transistor rise and fall time
I'm trying to emulate an automotive sensor with AVR and transistors.
I have three resistors connected in series.
Using AVR digital outputs (5V) to drive the transistors base, I "short circuit" to ...
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0answers
10 views
Deploying program from Atmel Studio or Avr dude to Atmel “XMEGA-A3BU Xplained”
Im attempting for the last 3-4 days to connect the Atmel dev board to the computer in order to either load the .elf or hex file to the bootloader in order to turn on the LED based for an assignment.
...
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0answers
18 views
Deployoing compiled program from Atmel Studio or Avr dude to Atmel “XMEGA-A3BU Xplained”
Im attempting for the last 3-4 days to connect the Atmel dev board to the computer in order to either load the .elf or hex file to the bootloader in order to turn on a LED.
Im following instructions ...
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2answers
360 views
Communicating between 2 different microcontrollers
My Arduino runs at 16MHz clock speed; another microcontroller runs at clock speed of 13MHz. If I send digital output directly from an output pin of the former to input pin of the latter, there will be ...
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1answer
47 views
Have I bricked my ATMEGA3328p by setting
I was playing around with setting the "system clock prescalar" (CLKPR).
I'm now in a situation where I can see that the clock is 244.9KHz, using my logic analyser and the "Clock output on PORTB0" ...
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3answers
547 views
Is the ATMEGA328P's serial baud rate quantised?
I'm using an ATMEGA328p, running from its internal oscillator (divided by 8 = 1MHz).
I've (roughly) measured the oscillator output, using my Salae logic analyser, as ranging from 960KHz to 1000KHz, ...
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1answer
72 views
Why does my AVR microcontroller not work without AVR DRAGON?
I have the most annoying problem I have ever come across. The company I worked have an embedded device of theirs and the main designer left the company. They told me to reprogramme the device with C ...
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1answer
45 views
Doing logical operations on Port PINS in Assembly
I'm trying to do those following the operations on PINS, but not sure how to do the not operation on a port, do xor ..etc?
would someone show me an excrept psesuod code ?
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1answer
38 views
AVR programmer necessary? [closed]
I have an atmega168pb and I've noticed that there is a difference in how the board can be programmed between Windows and Linux.
On Windows using Atmel Studio you can select an ISP interface and it ...
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0answers
23 views
Using UDRIE0 interrupt in ATmega168
I only have some limited knowledge in interrupts.
This is what I understand about following ISR functions
ISR(USART_RX_vect) will get called when a new data ...
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1answer
57 views
AVR ATMEGA328p Blinking Example
I wanted to test a simple blinking script on my ATMEGA328p. The breadboard setup (tested and works fine). But the LED does not blink. I probed the voltages across the board and they are showing up ...
3
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2answers
127 views
SPI Flash Memory with ATMega1284
I have connected a SST26VF064B 8Mb flash memory IC to an ATMeag1284 as shown in the following diagram. My plan is to talk to it using SPI.
Note that all capacitors in the schema are 100nF.
When ...
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1answer
63 views
ATtiny20 ISP, low voltage on MISO
I have been trying for quite some time to program a factory-new ATtiny20. After unsuccesfully trying with a USBASP and with ArduinoISP, I decided to take a look with my scope. Turns out the device is ...
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1answer
65 views
AVR - strange communication between ATmega8A and bluetooth module
I'm using ATmega8A-PU AVR microcontroller, and HC-05 bluetooth module on a breadboard.
What I'm doing here, is to connect to BT module from my mobile phone and toggle the LED state by sending ...
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1answer
45 views
LCD module not initializing
I've got a project where I need to use an LCD module, so I started pondering around with one (1602A).
So far I've wired it up with my microcontroller which is an Atmega168PA and written an ...
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1answer
88 views
which IDEs are available for Freertos with Stm32 IDE for Linux? [closed]
Is there any IDE available for Freertos or Stm32 for specifically only for Linux other than Keil uvision. because I found out that Keil uvision is the most stable IDEs available out there for embedded ...
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1answer
80 views
Generating 1 second with avr and timer 0 for Atmega32A
dears:
we have to Generate 1 second with atmega32A and mikrobasic software.
so I have configured timer 0 and avr with this way:
...
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1answer
46 views
IHave a problem with ADC in AVR
Hello.,I'm working on a project and I didn't get that
How I change the range from 0 to 1042(ADC 10bit)
To the range from 0 to 5
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1answer
62 views
Help with Atmega32u4 custom PCB
I have attempted to design my own custom Atmega32u4 board, but when I assembled it it didn't show up in windows device manager. I fixed the problem where I forgot to connect VBUS to VCC with a jumper ...
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2answers
191 views
Timer0 overflow interrupt does not work on ATtiny10
I am trying to use the Timer0 overflow interrupt to make a little project.
I used such a timer in the ATtiny45 and it worked, but with ATtiny10 no result.
So I tried an easy LED blinking program and ...
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2answers
149 views
AVR bitwise operation: making a NOT with a microcontroller
I'm programming an ATtiny10, i have two spare pins, one of which is the external interrupt pin on PB2, and i want to write the inverse of that signal to PB1. I want to spare a component, since i have ...
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3answers
115 views
GPIO state of MCU (AVR) with no supply voltage
In general:
what state do the GPIOs of a MCU (an AVR in my case) have when there is no supply voltage and the MCU is "off". Am I right that the pins are floating as there isn't any "reference" for the ...
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2answers
50 views
Atmega88p with shift register 74hc595
I need to use a shift register to control multiple leds, but I need to control each one individually. The idea would be to send a buffer with the data, however I need to have several active leds and ...
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2answers
99 views
when dividing two integer result truncated to 0 [closed]
when i divide two integer and if the result is below like 0.987, then it become zero
...
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0answers
24 views
can't figure out why my micronucleus/V-USB setup doesn't work
I built a small attiny85-based board using vusb and essentially the schematic of the discontinued Sparkfun "AVR Stick" (at least on the usb/uC side; see https://www.sparkfun.com/datasheets/Widgets/AVR-...
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2answers
129 views
How to load immediate negative value in a register?
For example on 8-bit AVR given a register r16 I do something like ldi r16, 44 and this way I can give it positive values from 0 ...
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1answer
46 views
How to show a long sentence on character LCD by using bascom?
I want to show a long message that going to differ every time and it's 3 lines or less. This message comes from Sim900. I cant show the whole sentence on my 4x20 lcd. how can I print it in several ...
2
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1answer
95 views
Atmel Chip not recognized as USB device. How to troubleshoot
I've soldered the AT90USB1286 Chip on a PCB like on this circuit: Imgur
If I measure the pins, caps, resistors etc. with a multimeter, everything seems to be powered and fine. Reset button pulls to ...
2
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1answer
227 views
Atmega naming scheme (324p vs 328p)
I am looking into AVR chips (big fan) for a personal project. I need capabilities similar to Arduino Uno, so I recently compared Atmega 328p and Atmega 324p.
To my surprise the 324p has significantly ...
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1answer
56 views
AT90USB162 not detected in windows
I have an AT90USB162, have it set up like this:
I'm trying to program the chip using Atmel FLIP, but I can't because it's not detected.
What could be the problem and how can I fix it?
2
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1answer
64 views
Atmega32u - Ground in bus powered configuration
The Datasheet provies an example configuration for when the device is powered from the bus, and shows the bus Vss connected to ...
