I uploaded the basic blink sketch on atmega328p while the chip was on arduino(inbuilt led was blinking i checked) then i removed it and placed it on the breadboard now i powered up the chip with a supply of 5V(approx) placed a 16mhz oscillator and connected the led to pb5 and also set the reset pin to 5V using a resistor but the led doesn't blink any idea on what's going wrong?btw i also checked voltages using multimeter and it reads around 3V across gnd and vcc and at pb5 its only 0.02V w

 

Hi P16,
I circuit diagram would help, where are the GND & AVCC Pins #31,30 connected?
E
EDIT: I have chosen the wrong device for the pin numbers, but Gnd & AVCC need connection.

 

pin-7 Vcc
pin-8 and pin-22 GND

What is connected to pin-1 /RESET?

 

pin-7 Vcc
pin-8 and pin-22 GND

What is connected to pin-1 /RESET?


View attachment 306341

it's connected to 5V via a 10k ohm resistor.

 

We cannot see the connections to Vcc and GND on the breadboard. From the photo it would appear that the resistor on pin-1 is connected to GND. Try to use more distinctive colours for your jumper wires. Also, why is the resistor not going directly to pin-1?

 

We cannot see the connections to Vcc and GND on the breadboard. From the photo it would appear that the resistor on pin-1 is connected to GND. Try to use more distinctive colours for your jumper wires. Also, why is the resistor not going directly to pin-1?

Indeed, connect the resistor directly between pin-1 and pin-7.

 

Hi P16,
I circuit diagram would help, where are the GND & AVCC Pins #31,30 connected?
E
EDIT: I have chosen the wrong device for the pin numbers, but Gnd & AVCC need connection.

how should i connect them?

 

how should i connect them?

Pin-22 to pin-8, pin-20 to pin-7.

 

Hi,
Post a circuit diagram
Post #13..
E

 

Hi,
Post a circuit diagram
Post #13..
E

 

why

Pin-22 to pin-8, pin-20 to pin-7.

why is there a need to connect them in all the circuit diagram i could find they were left alone?

 

The 10K resistor connected to RST (Pin 1) should go to VCC, not ground.

 

The 10K resistor connected to RST (Pin 1) should go to VCC, not ground.

TS has battery upside down.

 

Connect pin-22 GND.

 

how should i connect them?

GND has to be connected to circuit ground - power supply negative. AVCC needs to be connected to the power supply positive.

Have you done this?

 

TS has battery upside down.

I was looking at the breadboard layout, not the schematic. The reset resistor is connected to the negative rail instead of the positive.

 

I was looking at the breadboard layout, not the schematic. The reset resistor is connected to the negative rail instead of the positive.

i
have fixed that still not working

 

For a start, toss the long leads. I use solid wire from telecom cables for my breadboard tests. And cut them to length so the wires are as short as possible.
See if you can get some Ethernet or data cables to use that wire.

Somewhere I have a length of 50 pair cable. That supplies lots of colours.

Here is an example drawing of a layout with short leads. This is just a quick example from Tinkercad and I could not find other bits to try to make your circuit.

 

You need to use at least 10 uf (with a .001 uf in parallel) for the VCC pins. I don't leave the AVCC floating -that was never recommended.

You really need to read this at least once:
http://ww1.microchip.com/downloads/...ign-considerations_applicationnote_avr040.pdf

 

Yes, power supply decoupling is VERY important. It is the foundation of your project. Like any foundation, you need a good one!