Circuit fails after adding 7805

Thread Starter

Mark1015

Joined May 15, 2020
16
Noob at the helm. I am attempting to use an Atmega328 on a board. I have the same circuit designed without the 7805 and it is fine. I tried to add the 7805 in and I get a convergence failed error after a few cycles. Not sure what is going on. Any ideas to perfect this circuit would be great. 9547803C-F4DE-48CC-A385-9A60E9EE5C12.png9547803C-F4DE-48CC-A385-9A60E9EE5C12.png
 

ronsimpson

Joined Oct 7, 2019
719
What is the thing in the red square? What is VIN? It looks like a computer board with onboard regulators. I think VIN should be 6 to 9 volts. I think but do not know, that power on VIN is regulated to make 5V and 3V3. Look to see if the "think" will work if VIN=5V.
1592789769086.png
 

Thread Starter

Mark1015

Joined May 15, 2020
16
It is an Arduino board. Vin is voltage in. I am thinking it is just an error with software and not the proper board I intend to use. I want to connect an atmega328 Arduino board
 

AlbertHall

Joined Jun 4, 2014
10,022
If this is arduino like, with an on board regulator, then as said above Vin needs 7V+ and your 7805 output should be connected to +5V pin, not Vin.
 

Thread Starter

Mark1015

Joined May 15, 2020
16
If this is arduino like, with an on board regulator, then as said above Vin needs 7V+ and your 7805 output should be connected to +5V pin, not Vin.
No. I am co
If this is arduino like, with an on board regulator, then as said above Vin needs 7V+ and your 7805 output should be connected to +5V pin, not Vin.
maybe this will help clear up what I am attempting
https://www.digikey.com/en/maker/projects/build-your-own-arduino-breadboard/f243b09293ae4e3189bda47a821bb97a
 

Thread Starter

Mark1015

Joined May 15, 2020
16
But your simulation has a box with 3V3, 5V, and Vin pins. The bare chip has only the 5V pin. What exactly does your simulator think it is simulating?
But your simulation has a box with 3V3, 5V, and Vin pins. The bare chip has only the 5V pin. What exactly does your simulator think it is simulating?
All i was trying to do wasadd the voltage regulator per the building your own Arduino. I am thinking the simulator is treating the Arduino as an assembler board. Was just using the Arduino to utilize the 4017
 

djsfantasi

Joined Apr 11, 2010
6,505
It looks to me that you’re trying to simulate a DIY Arduino board with an “Arduino board”. What you want to use is an ATMega328 in your simulation circuit. This is the microcontroller chip. There isn’t a ATMega328 “board”!
 

Thread Starter

Mark1015

Joined May 15, 2020
16
It looks to me that you’re trying to simulate a DIY Arduino board with an “Arduino board”. What you want to use is an AtMega338P in your simulation circuit.
Correct. I guess that is what I was trying to say. The simulator only had the single Arduino
 

narkeleptk

Joined Mar 11, 2019
465
You need to run the Vin to more then one of the inputs on the atmega328. Its like 3 that needs to be hooked up if I remember correctly. Maybe that is why its not working. Pretty sure you need a pull down resister on the reset as well? or maybe thats depending on the code.. Don't really know there but I know when i build atmega328 stand alone's I always use one.
 

djsfantasi

Joined Apr 11, 2010
6,505
Correct. I guess that is what I was trying to say. The simulator only had the single Arduino
But what I said was that you don’t want an Arduino. You want an ATMega328. The two aren’t the same. One is a microcontroller board or system. The other is a chip, which the board is built with
 

Thread Starter

Mark1015

Joined May 15, 2020
16
But what I said was that you don’t want an Arduino. You want an ATMega328. The two aren’t the same. One is a microcontroller board or system. The other is a chip, which the board is built with
What I am attempting to do is have the atmega328 chip a 328p in this case on a board. Use my Arduino uno to upload a sketch onto the 328p chip. Then the chip will run the sketch as designed
 

djsfantasi

Joined Apr 11, 2010
6,505
So I hear that you want an Arduino board powered by an external 7805 (and not use the internal voltage regulators).

The 5V output of the external regulator should go to the 5V pin of the Arduino. As others have commented, connecting the output to the Vin pin won’t work. The Arduino board won’t be powered.
 

Thread Starter

Mark1015

Joined May 15, 2020
16
So I hear that you want an Arduino board powered by an external 7805 (and not use the internal voltage regulators).

The 5V output of the external regulator should go to the 5V pin of the Arduino. As others have commented, connecting the output to the Vin pin won’t work. The Arduino board won’t be powered.
Yes. A diy Arduino assembly if you will using the atmega328 chip. In a nutshell I have some atmega328 chips a bunch of capacitors and other parts I am finding a use for.
 

djsfantasi

Joined Apr 11, 2010
6,505
But you have a completed commercial Arduino board to use in uploading sketches? Is this correct?

Just to be sure. You understand that an ATMega328 is NOT an Arduino and vice versa? I ask because it appears that you DON’T understand...
 
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