All Questions
105
questions
4
votes
2
answers
1k
views
Transmitting from PC via USART to MCU working but very slow
I am sending a small 16-Bit RGB BMP image file from my Linux PC via USART (with a loosely wired USB to serial converter) to an AVR ATmega MCU sitting on a breadboard, running at 8 MHz with the ...
- 551
0
votes
1
answer
83
views
Software serial not sending the first byte correctly
I implemented the following program to send data to a serial monitor.When I run it, I expect to see abcd but I always see ⸮bcd:
<...
- 475
6
votes
1
answer
460
views
How does USART know which port to use for IO?
I'm trying to learn to use USART on an ATmega328P. I'm using this datasheet.
I'm using the following code to echo characters I type on my terminal:
...
- 475
0
votes
0
answers
128
views
What happens to an AVR UART's XCK pin when running in an asynchronous mode?
The question concerns AVR128DB32 but I don't happen to have a device available at hand to answer my own question by verify its behaviour on my workbench.
Reading the data sheet for that ...
- 190
0
votes
0
answers
466
views
Store Receive bytes from UART as a string in BASCOM AVR
I'm working on receive interrupt uart and I wanna store all of data as a string . I also catch data (one by one) byte until receiving ETX . When I catch ETX ,it means end of datas.
unfortunately, my ...
0
votes
1
answer
104
views
AVR ATMEGA32A UART not send and receive data unless programmer is connected
The code in micro is to turn a LED on when it receives "1" from UART and off when receives "0".
For VCC I use a phone adapter (5V, 0.7A) which works properly and is suitable for ...
0
votes
1
answer
114
views
Unnexpected Behaviour From Software UART On ATtiny84A AVR
I am trying to implement a software UART for the ATtiny84A, as it does not come with a UART out of the box.
The following is an example of the UART TX:
...
- 245
0
votes
1
answer
123
views
What to consider when choosing a crystal
I'm working on a Datalogger project power by a battery that needs to take sensor measurements and broadcast the parameters to a server.
The power source to the CPU is 3.3Vcc from the battery.
The ...
1
vote
0
answers
132
views
atmega328p UART rx pin
I have simple co2 meter using atmega328p as uC (Arduino mini Pro board actually). Microcontroller is sending measurements over FT232RL to a PC host (one way communication from AVR to PC), but this ...
- 113
0
votes
1
answer
212
views
UART doesn't transmit all characters when using UDREn interrupt
Note: I am beginner :) MCU: Atemega328p
In Method 1, I am using a UDRn data register empty interrupt once the transmit buffer is empty and inputting characters from ...
- 459
1
vote
2
answers
261
views
Does this interrupt improve performance even with while loop in ISR?
Note: I am a beginner :) MCU: Atmega328p
Which program below burdens the CPU the least? Would it be a significant difference?
Objective: to make a more "efficient" serial monitor by ...
- 459
0
votes
2
answers
495
views
Checking and reading bits using while loops
Note: I am a beginner :) MCU: Atmega328p
I am struggling to understand how reading registers using while loops work in Embed C:
For example AVR-C USART Protocol:
...
- 459
1
vote
2
answers
475
views
Why would you right shift 8 bits for 8 bit register?
MCU: Atemega328P Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-7810-Automotive-Microcontrollers-ATmega328P_Datasheet.pdf (Page 143 - USART)
Note: I am beginner :)
Using the BAUD ...
- 459
0
votes
1
answer
179
views
Unsigned int values gives negative number above the halfway point of max byte value?
MCU: Atemga328P: Datasheet:https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-7810-Automotive-Microcontrollers-ATmega328P_Datasheet.pdf
Note: I am a beginner :)
Considering a 2 byte ...
- 459
1
vote
1
answer
126
views
Why UART voltage level on ATMEGA64A-AU are different?
Coming from this question I tried to measure voltage on RX1 and TX1 on ATMEGA64A-AU (the second USART) the RX1 voltage is about 3 volt and TX1 is 5 volt(straight out of the chip) which I've provided ...
- 19