My blurtooth model doesn't work after make the ATmega328 chip standalone

I have a bluetooth model connected on my Arduino Uno, it works fine on the Arduino board.

After I make the chip standalone on the breadboard, the blutooth doesn't work fine, It can be connected but no data transfer.

the RX and TX pins is correct for sure.

so anyone can help me?

NimitzDEV:
After I make the chip standalone on the breadboard, …

Is that with a crystal?

NimitzDEV:
I have a bluetooth model connected on my Arduino Uno, it works fine on the Arduino board.

After I make the chip standalone on the breadboard, the blutooth doesn’t work fine, It can be connected but no data transfer.

the RX and TX pins is correct for sure.

so anyone can help me?

A schematic of how you have it connected would probably help a whole lot. Or shall we just guess?

Delta_G:
A schematic of how you have it connected would probably help a whole lot. Or shall we just guess?

I connected the TX pin on bluetooth with RX pin on ATmega328 directly (also RX -> TX)

The same connections on my Arduino Uno works fine

i will post my schmatic later

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@NimitzDEV, please use Reply or the Quick Reply at the bottom.

sorry sorry
something went wrong at that time.....

The schematic has to include what you did for the standalone circuit, many of the circuits on the net are bad and do not work correctly because they miss out too many parts.

Grumpy_Mike:
The schematic has to include what you did for the standalone circuit

ditto^

full disclosure please... piece-meal doesnt help put the 'big picture' out there for analysis

NimitzDEV:
I connected the TX pin on bluetooth with RX pin on ATmega328 directly (also RX -> TX)

The same connections on my Arduino Uno works fine

i will post my schmatic later

I guess the question was more aimed at making sure you had the right pins on the 328. You'd be amazed how many folks get those messed up and then we chase our tails for three pages only to find out the OP had the chip backwards or read the pin numbers wrong.

Or failed to provide power and ground to all the power and ground pins or missed out the
decoupling cap(s)....

or missed out the decoupling cap(s)…

My bet is that he doesn’t even know what they are.

Chatty isn’t he.