Questions tagged [atmega32u4]

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Connecting USB-C port with ATmega32u4 - Questions

I'm a beginner when it comes to schematics. I'm attempting to create a USB-C + Atmega32u4 schematic. Later I will add cols and rows for keyswitches (usb keyboard). Below is the schematic I came up ...
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2 answers
55 views

How to test if a ATMega16u2 is working

I have designed a custom ATmega16u2 board, however, I cannot connect to it using USB. All connections seem to be correct, and I have checked that the voltage regulator is working, regulating it to 3....
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31 views

ATMega32u4 minimum system clock for USB 2.0

I am trying to cut down the power consumption for an ATMega32u4. The datasheet says, for USB 2.0 it needs an external clock, which it uses to generate a 48 MHz clock by multiplying the external clock ...
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2 votes
1 answer
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Strange ATmega32 behavior with assembly code

I posted a kind of similar question recently, but it was not that organized, so here I am trying again :) I wrote this short assembly code to blink an LED at different intervals depending on the state ...
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2 answers
103 views

AVR reset pin capacitor causes chip to enter bootloader on powerup

I have a circuit using an ATmega32U4 and am using the Arduino Leonardo/Micro Caterina bootloader (the one that comes with arduinoIDE v1.8.13). The problem I am having is on power-up (via USB ...
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3 votes
1 answer
305 views

ATmega32u4 reset circuit and bootloader

I have an ATmega32u4 which I have configured to run its application by default at boot, and to run the bootloader (standard DFU USB bootloader from Microchip) when the reset button is pressed. I ...
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1 answer
109 views

ATmega32U4 I/O Pin Alternate Functions

I am using an ATmega32U4 as a master with 2 slave ADCs (AD7739), ADC1 and ADC2. The two ADCs are identical. The SS, SCLK, MOSI, and MISO for ADC1 correspond to ports PORTB0,1,2, and 3 respectively, ...
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2 votes
4 answers
476 views

PCB design review (ATMEGA32U4)

I have been trying to make a watch for the past few months, but all my prototypes have been unsuccessful. So, to try ironing out some problems, I made a practice PCB to try testing my base Atmega32u4 ...
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3 answers
95 views

Does a USB port provide enough power for my LED project?

I'm not quite sure whether or not my LEDs will draw too much current. I can't put the schematic right now, but basically I'm using just using the power line from the USB 2.0 port on my board, and it ...
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0 answers
53 views

Feather 32u4 too much current draw

I am trying to build a battery-powered application using the Feather 32u4. I need a timer to trigger every 120 seconds (although Timer1 with it's 8 second limit would suffice for the beginning), thus ...
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1 vote
0 answers
43 views

ATMega32u4 Timer code not working

The following timer code running on a 8Mhz ATMega32u4 should toggle the onboard LED every second, and calling the ISR code manually does so. Yet, the ISR does not seem to get called. Could anyone ...
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61 views

How to change LUFA default 8MHz crystal setting?

I have an Atmega32u4 micro controller with minimum hardware design. It has an embedded USB compatibility which can be enable/used with some software like LUFA. Everything works fine (the computer ...
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0 answers
28 views

32U4 based board sometimes does not run setup

I have a custom PCB using 32U4. Sometimes when I switch the board on, the code of setup() function does not run. But this is quite unfrequent, the board usually works fine. This just happens from time ...
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0 answers
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Issue with daisy chained arduinos and serial communication

I have a setup with a 32U4 based board and 2 daisy chained 328p based boards. Boards are connected via 4 wires : VCC, GND, TX, RX 32U4 is powered by USB Daisy chain is : ...
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2 votes
1 answer
138 views

Can't program ATmega with ICSP on custom pcb

I'm fairly new to PCB design, and I've been trying to program the microcontrollers on the board I designed with no luck. The board uses an ATmega32u4 and an ATmega328P. I've been trying to program ...
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1 vote
0 answers
57 views

Bidirectional logic level converter with voltage regulator and 5 volt microcontroller

I have to use an N-channel enhancement mode Mosfet based Bidirectional logic level converter along with a fixed 3.3 voltage regulator along with 5 volt micro controller. I am powering the low voltage ...
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0 answers
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Atmega16U4 (Hardware USB) does not show up as DFU device on device manager

I am trying to get the Atmega16U4 to show up in windows device manager. Right now, when I connect the atmega16U4 through USB to the computer it does not do anything (does not even play the USB ...
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2 answers
128 views

PCB with multiple Arduinos and onboard hub

I'm designing a PCB for an astronomical observatory which needs several Arduino Micro to control different devices. Since the circuit must fit a very small space, I'm putting an onboard USB hub to ...
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1 vote
1 answer
73 views

Cannot connect Arduino Uno REV3 ATmega16u2 serial connection to outside serial connection

I wanted to simply use the ATmega16u2 on my official Arduino Uno with a serial connection. I connected my Serial Board (where I can simply connect any serial connection and read it on my PC via Putty)...
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1 vote
0 answers
1k views

Why is my atmega32u4 not showing up as a USB device

I have an atmega32u4 as part of a PCB that I designed. The atmega32u4 comes with a USB bootloader and so I should just be able to plug it into my USB port and have it show up as a device. It doesn't ...
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0 answers
144 views

Can I communicate with an Atmega32U4 through USB during runtime?

I'm designing a PCB circuit to do PID control using sensor data to control a robot. I'm new to using micro-controllers other than Arduino and I'm having some trouble figuring out exactly how ...
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1 answer
281 views

How do I program an ItsyBitsy 32u4?

How do I load code onto a ItsyBitsy 32u4 without using the graphcial Arduino IDE? I've looked for "ItsyBitsy 32u4 programmer" and ItsyBitsy 32u4 bootloader".
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1 answer
615 views

Atmega32u4 USB and USART

I have an ATMega32u4. My question is about the bootloader section. How does this device pretend to be a com port while connected to USB? What makes the computer think it is a com port and how can I ...
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0 votes
1 answer
208 views

Atmega32u4 constant `1023` reading on ADC Channel

I can't share the schematics as they are not mine, I'm trying to add an analog thumbstick (4 pins, Vcc/GND/x/y) to my atmega32u4 powered keyboard. The thumbstick pins are connected to pins PB4 (ADC11)...
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1 vote
2 answers
421 views

Can I use the internal Atmega32u4 clock for USB applications?

I believe I can set a fuse in the atmega32u4 to tell it to use its internal clock rather than an external crystal. Would the internal clock be acceptable for using the microcontroller as a USB HID ...
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3 answers
603 views

What fuse to set to enable 16MHz clock on the atmega32u4

It's my first time attempting to program an Atmega32u4, or any microcontroller for that matter, on a custom board I got printed. avrdude has a weird output when I, for example, run this command: <...
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1 vote
1 answer
632 views

Issue with programming Atmega32u4 (lfuse memory not accessible using FLIP)

From my last question, I've managed to connect my Atmega32u4 to my computer. Now, when attempted to initialise the bootloader using avrdude, I get the following error message: ...
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2 votes
2 answers
7k views

How can I program an Atmega32u4 over USB with this schematic?

This is my first time trying to program an Atmega32u4. I made a PCB with the following schematic: Now I've soldered all the parts onto the PCB, and I've plugged a micro usb cable from my computer ...
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2 answers
249 views

ATmega stopped working after changing CKDIV8 fuse

I have ATmega32U4. I connected it via SPI programmer and in Atmel Studio I have read their signature properly. It was working. Then I cleared and programmed CKDIV8 fuse. Clock was set to internal RC. ...
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0 votes
1 answer
1k 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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3 votes
1 answer
786 views

ATMega32u4 VBUS and SMD Schottky Diode

I have spent quite a bit of time trying to work this out, but I just can't. I want to power my ATMEGA32U4 chip via USB, and at the same time send that USB +5V off to the circuit +5V bus per the ...
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2 votes
1 answer
154 views

Atmega32u - Ground in bus powered configuration

The Datasheet provides an example configuration for when the device is powered from the bus, and shows the bus Vss connected to ...
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0 votes
1 answer
77 views

Why PINxn with pullup reads zero when nothing is connected to it?

Consider the following C-program: ...
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0 votes
1 answer
309 views

Will other devices interfere with programming a ATmega32U4 if attached to SPI bus?

I’m designing a custom PCB around an ATMega32U4. The 32u4 will talk to another onboard component via the SPI bus. Since the SPI pins (MISO, MOSI, SCK) are also used for ISP programming could other ...
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0 votes
1 answer
1k views

Is my PCB layout ok? (ATMEGA32U4, WizNet W5500, Ethernet)

I want to design a device that listens to certain network communication and calculates a MIDI clock signal out of this information. The MIDI output is via classical MIDI port or via USB MIDI. I am ...
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0 votes
1 answer
362 views

i2c interference on coiled wire

Hello good day I been trying to build split keyboard using 2 pro micro. I'd been following let's split keyboard using qmk firmware. And the connection diagram of the i2c is this When doing it on ...
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0 votes
1 answer
89 views

Atmega32u4 Pin F0 output is only 3.64V, not 5.00V

Unlike F4 which outputs 5.0V, my F0 pin only outputs 3.64V. Is this normal? This is my code: ...
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0 votes
1 answer
652 views

4n25/35 optocoupler detect led on/off

Hey all i am just wondering if my drawing below is correct in order to have an arduino detect an on or off led on another board using a optocoupler? My thoughts of the above drawing is that when the ...
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2 votes
2 answers
2k views

Do I have to provide VCC to every VCC pin on Atmega32u4 MCU?

Atmega32u4 has 7 VCC pins. Can I connect 1 of the 7 VCC pins to the power supply to power the MCU, and use the rest of the VCC pins (6 of them) on the MCU to power other peripherals, such as LEDs?
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1 vote
2 answers
709 views

ATmega16u4 and ATmega32u4 i2c bug in Proteus AVR model?

I am trying to use i2c with ATmega16u4/ATmega32u4 in Proteus (version 8.5 SP1) and in my i2c code the following code line hangs the MCU: ...
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-1 votes
2 answers
2k views

ATmega32U4 with TXLED and RXLED as output pins and USB functionality

I use ATmel ATmega32U4 in a schematic which copies Arduino Leonardo almost completely. So, Caterina-Leonardo bootloader works fine with it. Unfortunately, I have run out of all available output pins. ...
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3 votes
2 answers
2k views

Re-purpose USB cable to carry I2C

I was wondering if it would be possible to connect an IO extender (MCP23017-E/SP) to an ATMega32u4-AU via an USB cable. I figured that if you connect up the SCL pin to the Data+ of the USB and the ...
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2 votes
2 answers
336 views

how to program the fuse bits of atmeta32u4 via the usb port?

here I have an avr development board with a core of type Atmega32u4. I can only access to the memory via a usb cable.The default fuse bits seem to enable the JTAG which I want to disable. ...
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0 votes
1 answer
628 views

Virgin Atmega32u4 USB ISP initialization failure

I custom made my own PCB to use Atmega32u4. It's really a clone of PJRC's Teensy 2.0. Unfortunately I cannot initialize any of my Atmel Store purchased Atmega32u4 using USBTinyISP. The schematic is ...
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