ATmega328p-pu off board problem

Other Hardware General Electronics
1

Hi,

I tried yesterday to connect and make a communication between 2x nRF's and got a problem,
the actual problem is not from the nRF but the actual ATmega328p-pu, as start i thought that i
done few bad connections but i remembered that i already worked like that in the past and worked.

Well the actual problem i got is: I upload a single blink example on Uno board its working but when
i get off the atmega and plug it in a homemade board just with 2 caps and crystal the atmega
stop working.
I plug a 3.3v power on the GND-VCC of the atmega i get power but the blink loop not working,
I uploaded other kind of codes and non of them working.

Now few people may ask about my board: I got soldered pins for the atmega and 22pf and 16Mhz crystal
that's all, I worked with the board in the past and worked really well. But now im not really sure why don't wanna loop the codes.

I test the same chip on the Uno board and working really well after that i unplug the chip and test in on bread boad with crystal and not working. What I am doing wrong? Probably nothing but why it's not working?

2

I don't think the 328 will run at 16MHz and 3.3V. Check the data sheet.

3

it's a ATmega328p-pu it's low power chip but in this case I tried just few min ago with 5v and still don't working
i put back the chip on Uno board and it's working but on the breadboard it's not O_o

4

Does the breadboard have 0.1uF caps on the VCC and AVCC pins?
Does the breadboard have 10K pullup on the reset pin?
What else is connected on the breadboard?

5

I pluged 5v on a ATmega328p-pu on bradboard with this code: .

/*
  Blink
  Turns on an LED on for one second, then off for one second, repeatedly.
 
  This example code is in the public domain.
 */
 
// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;
int led2 = 12;
int led3 = 11;
int led4 = 10;
int led5 = 9;
int led6 = 8;
int led7 = 7;
int led8 = 6;
// the setup routine runs once when you press reset:
void setup() {                
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);    
  pinMode(led2, OUTPUT);     
  pinMode(led3, OUTPUT);     
  pinMode(led4, OUTPUT);     
  pinMode(led5, OUTPUT);     
  pinMode(led6, OUTPUT);     
  pinMode(led7, OUTPUT);     
  pinMode(led8, OUTPUT);       
}

// the loop routine runs over and over again forever:
void loop() {
  digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
  digitalWrite(led2, HIGH);
  digitalWrite(led3, HIGH);
  digitalWrite(led4, HIGH);
  digitalWrite(led5, HIGH);
  digitalWrite(led6, HIGH);
  digitalWrite(led7, HIGH);
  digitalWrite(led8, HIGH);
  delay(1000);               // wait for a second
  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
  digitalWrite(led2, LOW);
  digitalWrite(led3, LOW);
  digitalWrite(led4, LOW);
  digitalWrite(led5, LOW);
  digitalWrite(led6, LOW);
  digitalWrite(led7, LOW);
  digitalWrite(led8, LOW);
  
  delay(1000);               // wait for a second
}

Uploaded this code from a arduino Uno then took the chip on a bread board with 2x 22pf and 16Mhz crystal
start testing with some wires pluged on led GND and with the + of the led testing each pin in the code
from the pin 13 and below, when i arrived at the pin 9 there wasn't any kind of blinking just a HIGH led,
the rest bellow pins didn't even blink, from the pin 8 and low all pins was like dead, LOW.

Tested the same chip with the same code on the Uno board, all pins worked great.

What's wrong? what I'm doing wrong?
I worked before on breadboard but didn't had problems.

Breadboard:
Using a 5v power sup. GND-VCC
2xpF caps
16Mhz crystal
Led (for testing)

6

I think he answered the question a couple of times, CrossRoads.

Just a xtall, loading caps, LED, and the mega. No pull-up on the reset pin. no filt on the supply.

Op: you went a little too far in the 'bare bones' direction. Left out some pretty important pieces......

If the chip works in the uno board, but does not in your bread board, obviously the problem is in the bread board implementation. Re-read responses by CrossRoads.

7

Domino60:
Breadboard:
Using a 5v power sup. GND-VCC
2xpF caps
16Mhz crystal
Led (for testing)

Where are the 0.1uf capacitors between Vcc and ground? You want one for each Vcc pin, located as close to the chip as possible. This is true of any IC - you always need the decoupling cap(s) or all sorts of crazy things can happen.

8

You must have AVcc within 0.3V of Vcc too, with its own decoupling capacitor ideally.